Overlay measurement device

Abstract

The present invention discloses an overlay measurement device, which includes a measurement chamber, a measurement mechanism and a regulation mechanism. The measurement chamber is used to place a wafer with overlay marks. The measurement mechanism is arranged in the measurement chamber and is used to measure the overlay marks of the wafer. The regulation mechanism is used to regulate the temperature of the measurement chamber. Specifically, when it is necessary to detect the wafer, the wafer is placed in the measurement chamber, and the regulation mechanism is used to adjust the temperature in the measurement chamber so that the temperature in the measurement chamber is maintained at a certain level to meet the measurement requirements of the measurement mechanism. The measurement mechanism measures the overlay marks on the wafer. Since the temperature in the measurement chamber meets the measurement requirements, the influence of temperature on the measurement data is avoided, and the situation of data misreading is eliminated, thereby accurately reflecting the processing quality of the wafer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and particularly to an overlay measurement device. Background Art

[0002] The information provided in this section is only background information related to the present disclosure, and it is not necessarily prior art.

[0003] In the process of semiconductor manufacturing, wafers are processed by means of overlay, and after processing, the wafers need to be inspected for overlay marks to ensure the processing quality of the wafers.

[0004] When inspecting the overlay marks, a focus detection device is usually used. The existing focus detection device is greatly affected by surrounding environmental factors (such as temperature, humidity, and pressure), resulting in misreading of the focus detection device, leading to measurement errors and unable to accurately reflect the processing quality of the wafers. Summary of the Invention

[0005] The present invention provides an overlay measurement device, which includes:

[0006] A measurement chamber for placing a wafer with overlay marks;

[0007] A measurement mechanism disposed in the measurement chamber for measuring the overlay marks of the wafer;

[0008] A regulation mechanism for regulating the temperature of the measurement chamber.

[0009] According to the overlay measurement device of the present invention, when it is necessary to inspect a wafer, the wafer is placed in the measurement chamber, and the temperature in the measurement chamber is adjusted by the regulation mechanism so that the temperature in the measurement chamber is maintained at a certain level to meet the measurement requirements of the measurement mechanism. The measurement mechanism measures the overlay marks on the wafer. Since the temperature in the measurement chamber meets the measurement requirements, the influence of temperature on the measurement data is avoided, and the situation of data misreading is eliminated, thereby accurately reflecting the processing quality of the wafer. Brief Description of the Drawings

[0010] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0011] Figure 1 Schematically shows a structural diagram of the overlay measurement device according to the present invention.

[0012] The reference numerals are as follows:

[0013] 100 is a lithography measurement device;

[0014] 10 is a measurement chamber;

[0015] 11 is a connection structure;

[0016] 20 is a measurement mechanism;

[0017] 21 is a focusing component;

[0018] 211 is an objective lens, 212 is a first acquisition unit, 213 is a control unit, 214 is an adjustment unit, and 215 is a second acquisition unit;

[0019] 22 is an interference component;

[0020] 221 is a light source, 222 is a laser, and 223 is a reference signal detection unit;

[0021] 30 is a regulation mechanism;

[0022] 31 is a detection part;

[0023] 40 is a clamping part;

[0024] 200 is a wafer;

[0025] 201 is a lithography mark. Detailed implementation manners

[0026] Hereinafter, the exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0027] It should be understood that the terms used herein are for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless otherwise clearly specified in the context, the singular forms "a", "an", and "the" as used herein may also include the plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the order of performance is explicitly stated. It should also be understood that additional or alternative steps may be used.

[0028] Although terms such as first, second, and third may be used in the text to describe multiple elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as "first" and "second" and other numerical terms do not imply an order or sequence when used in the text. Thus, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0029] For ease of description, spatial relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure to another element or feature, such as "inside", "outside", "inner side", "outer side", "below", "beneath", "above", "over", etc. Such spatial relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, an element described as "below" or "beneath" another element or feature will then be oriented "above" or "over" the other element or feature. Thus, the exemplary term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used in the text are interpreted accordingly.

[0030] As Figure 1 shown, according to an embodiment of the present invention, the present invention provides an overlay measurement device 100, which includes a measurement chamber 10, a measurement mechanism 20, and a regulation mechanism 30. The measurement chamber 10 is used to place a wafer 200 with an overlay mark 201. The measurement mechanism 20 is disposed in the measurement chamber 10 and is used to measure the overlay mark 201 of the wafer 200. The regulation mechanism 30 is used to regulate the temperature of the measurement chamber 10. Specifically, when it is necessary to detect the wafer 200, the wafer 200 is placed in the measurement chamber 10, and the regulation mechanism 30 is used to adjust the temperature in the measurement chamber 10 so that a certain temperature is maintained in the measurement chamber 10 to meet the measurement requirements of the measurement mechanism 20. The measurement mechanism 20 measures the overlay mark 201 on the wafer 200. Since the temperature in the measurement chamber 10 meets the measurement requirements, the influence of temperature on the measurement data is avoided, and the situation of data misreading is eliminated, thereby accurately reflecting the processing quality of the wafer 200.

[0031] It should be understood that the measurement chamber 10 is a relatively enclosed space. By using the regulation mechanism 30 to intervene in the measurement chamber 10, the temperature of the measurement chamber 10 can meet the measurement requirements of the measurement mechanism 20, that is, the temperature in the measurement chamber 10 has little or no influence on the measurement mechanism 20.

[0032] It should be noted that when etching the wafer 200, the wafer 200 is often subjected to multiple overlay exposures. In order to detect the overlay quality of the wafer 200, when using the overlay measurement device 100 to measure the overlay marks 201 on the wafer 200 (the overlay marks 201 usually include two types, one is the BIB mark and the other is the AIM mark), as the overlay pattern becomes smaller and narrower, the overlay mark 201 also evolves into a segmented structure, that is, the overlay mark 201 is composed of several segments. When using the measurement device to measure (measuring data such as the width, length of the overlay mark 201 and the width between adjacent overlay marks 201), due to the influence of temperature, adjacent signals interfere with each other, resulting in misreading of the data. Therefore, by setting the wafer 200 in the measurement chamber 10 and regulating the temperature in the measurement chamber 10 through the regulation mechanism 30, the influence of temperature on the measurement process is reduced or eliminated to ensure the accuracy of the measurement data.

[0033] In addition, the overlay mark 201 is located in the scribe lane, and the width of the scribe lane is usually 60μm. The overlay mark 201 of the present invention adopts the BIB (Box-In-Box) mark.

[0034] It is further understood that as Figure 1 shown, the regulation mechanism 30 includes a gas source (not shown in the figure) and a control component. The gas source is connected to the measurement chamber 10 through a pipeline. The gas source is used to supply gas with a certain temperature to the measurement chamber 10 to maintain the temperature of the measurement chamber 10 at a preset temperature. The control component is used to turn on or off the pipeline. Specifically, the gas source is connected to the measurement chamber through the pipeline, and the control component is arranged on the pipeline. By controlling the pipeline with the control component, it can be realized whether the gas source is connected to the measurement chamber 10. When it is necessary to adjust the temperature in the measurement chamber 10, the control component opens the pipeline, so that the gas source is connected to the measurement chamber 10. The temperature of the gas stored in the gas source is higher than the temperature of the measurement chamber 10. In the present invention, the gas in the gas source is called high-temperature gas. The high-temperature gas enters the measurement chamber 10 through the pipeline (as Figure 1 shown, in Figure 1Among them, the black dotted arrow indicates high-temperature gas). After the temperature in the measurement chamber 10 stabilizes at the preset temperature and is maintained for a period of time, the control component disconnects the pipeline, and uses the measurement mechanism 20 to measure the alignment mark 201 of the wafer 200. The temperature in the measurement chamber 10 meets the measurement requirements of the measurement mechanism 20, thereby reducing or eliminating the influence of temperature on the measurement process and improving the accuracy of the measurement data.

[0035] It should be understood that the gas source is connected to the measurement chamber 10 through a pipeline. At least some components of the control component are arranged on the pipeline and cooperate with the pipeline. When the gas source needs to be connected to the measurement chamber 10, the control component performs an operation to open the pipeline. When the gas source needs to be disconnected from the measurement chamber 10, the control component performs an operation to close the pipeline. By setting the control component, the convenience of connecting or disconnecting the gas source from the measurement chamber 10 is improved.

[0036] It should be noted that the gas stored in the gas source is high-temperature gas, that is, the temperature and pressure of the high-temperature gas are both greater than the temperature and pressure in the measurement chamber 10. When the high-temperature gas enters the interior of the measurement chamber 10, due to the increase in space, the temperature of the high-temperature gas decreases. By continuously introducing high-temperature gas into the measurement chamber 10, the temperature in the measurement chamber 10 continuously rises. When the temperature in the measurement chamber 10 reaches the preset temperature (the temperature required for the measurement mechanism 20 to measure), the input of high-temperature gas into the measurement chamber 10 stops, so that the measurement conditions of the measurement mechanism 20 are met. At this time, when measuring the alignment mark 201 of the wafer 200, the accuracy of the measurement is effectively guaranteed.

[0037] In addition, the control component includes a temperature sensor (not shown in the figure). The temperature sensor is arranged in the measurement chamber 10 and is used to detect the temperature in the measurement chamber 10. The control component is based on the temperature feedback by the temperature sensor to realize the control of the pipeline connection or disconnection. That is, when the temperature is lower than the preset temperature, the control component opens the pipeline according to the result feedback by the temperature sensor. When the temperature is greater than or equal to the preset temperature, the control component disconnects the pipeline according to the result feedback by the temperature sensor. By setting the temperature sensor, the accuracy of the temperature control in the measurement chamber 10 is improved, and the measurement accuracy of the alignment mark 201 of the wafer 200 is further improved.

[0038] In addition, the number of temperature sensors can be multiple. The multiple temperature sensors are dispersedly arranged in the measurement chamber 10. The multiple temperature sensors are used to synchronously detect the temperature in the measurement chamber 10, and the temperatures feedback by each temperature sensor are averaged. By comparing the average value of the temperature with the preset temperature and controlling the connection or disconnection of the pipeline according to the comparison result, it is further ensured that the temperature of the measurement chamber meets the measurement requirements of the measurement mechanism 20, and the accuracy of the measurement data is further improved.

[0039] Further, the preset temperature is 22°C. Specifically, when it is necessary to measure the alignment mark 201 of the wafer 200, the control component opens the pipeline connecting the measurement chamber 10 and the gas source, so that the high-temperature gas in the gas source enters the measurement chamber 10 through the pipeline. The entry of the high-temperature gas into the measurement chamber 10 raises the temperature of the measurement chamber 10. When the temperature in the measurement chamber 10 reaches the preset temperature, the control component disconnects the pipeline. At this time, the temperature in the measurement chamber 10 is maintained at the preset temperature to avoid the influence of temperature on the measurement process and improve the accuracy of the measurement data. The measurement mechanism 20 has the best measurement effect under the temperature condition of 22°C. By setting the preset temperature to 22°C, the accuracy of the measurement structure is further improved.

[0040] In addition, in other embodiments, the value of the preset temperature can also be other values. The setting of the preset temperature is specifically determined according to data such as the pressure and humidity of the measurement chamber 10. Here, regarding how to set the preset temperature, the present invention will not be further elaborated.

[0041] Further, the control component includes a valve (not shown in the figure) and a controller (not shown in the figure). The valve is arranged on the pipeline, and the controller is electrically connected to the valve for controlling the opening and closing of the valve. Specifically, the measurement chamber 10 is connected to the gas source through the pipeline. The valve is arranged on the pipeline and electrically connected to the controller. When a temperature sensor is provided in the measurement chamber 10, the temperature sensor is also electrically connected to the controller. The temperature sensor feeds back the detected temperature in the measurement chamber 10 to the controller. The controller compares the temperature fed back by the temperature sensor with the preset temperature. When the temperature in the measurement chamber 10 is lower than the preset temperature, the controller sends an opening instruction to the valve. After receiving the opening instruction, the valve switches to the open state. At this time, the gas source can be connected to the measurement chamber 10 through the pipeline, and the high-temperature gas in the gas source enters the measurement chamber 10 through the pipeline to realize the heating of the measurement chamber 10. When the temperature in the measurement chamber 10 is greater than or equal to the preset temperature, the controller sends a closing instruction to the valve. After receiving the closing instruction, the valve switches to the closed state. At this time, the gas source is disconnected from the measurement chamber 10. By setting the valve and the controller, the automatic control of the temperature in the measurement chamber 10 is realized, thereby improving the convenience of measuring the alignment mark 201 of the wafer 200 and effectively enhancing the measurement efficiency.

[0042] It should be noted that the preset temperature is stored in the controller. The controller receives the current temperature of the measurement chamber 10 fed back by the temperature sensor, compares the current temperature with the preset temperature, and controls the valve according to the comparison result.

[0043] In addition, in the embodiment of the present invention, the valve is configured as a solenoid valve structure. The valve with a solenoid valve structure is convenient to control, has a rapid response, and a good on-off effect, effectively meeting the usage requirements.

[0044] Furthermore, both the valve and the pipeline are made of high-temperature resistant structures and materials, effectively avoiding the occurrence of high-temperature gas leakage and ensuring the safety of the measurement process.

[0045] Further, as Figure 1 shown, the control component further includes a detector 31. The detector 31 is arranged in the measurement chamber 10 and electrically connected to the controller. The detector 31 is used to collect the pressure in the measurement chamber 10. Specifically, when it is necessary to measure the overlay mark 201 of the wafer 200, the temperature sensor feeds back the detected temperature in the measurement chamber 10 to the controller. The controller compares the temperature fed back by the temperature sensor with the preset temperature. When the temperature in the measurement chamber 10 is lower than the preset temperature, the controller issues an opening instruction to the valve. After receiving the opening instruction, the valve switches to the open state. At this time, the gas source can be communicated with the measurement chamber 10 through the pipeline, and the high-temperature gas in the gas source enters the measurement chamber 10 through the pipeline to realize the heating of the measurement chamber 10. When the temperature in the measurement chamber 10 is greater than or equal to the preset temperature, the controller issues a closing instruction to the valve. After receiving the closing instruction, the valve switches to the closed state. At this time, the gas source is disconnected from the measurement chamber 10, and the detector 31 feeds back the detected pressure in the measurement chamber 10 to the controller. The controller corrects the measurement mechanism 20 according to the pressure fed back by the detector 31 to eliminate the influence of pressure on the measurement process, further improving the accuracy of the detection data.

[0046] It should be noted that the measurement chamber 10 is a relatively closed space, and the pressure of the high-temperature gas in the gas source is higher than the pressure in the measurement chamber 10. When the high-temperature gas is introduced into the interior of the measurement chamber 10, the pressure inside the measurement chamber 10 increases synchronously while the temperature rises. At this time, if the pressure of the measurement mechanism 20 is not corrected, the accuracy of the data measured by the measurement mechanism 20 cannot be guaranteed. By using the detector 31 to detect the pressure in the measurement chamber 10, the controller corrects the detection mechanism according to the detected data, so that the measurement result of the measurement mechanism 20 is the corrected result, further ensuring the accuracy of the measurement.

[0047] In addition, a pressure correction data table is stored in the controller. The controller corrects the pressure data by looking up the table according to the pressure data detected by the detector 31 to ensure the measurement accuracy of the measurement mechanism 20.

[0048] In addition, the control component may further include a humidity sensor. The humidity sensor is disposed inside the measurement chamber 10 and electrically connected to the controller. The humidity sensor detects the humidity inside the measurement chamber 10 in real time and feeds the detected data back to the controller. The controller further corrects the measurement mechanism 20 in combination with the detected humidity data to eliminate the influence of humidity on the measurement result, making the data detected by the measurement mechanism 20 more accurate.

[0049] Furthermore, as Figure 1 shown, the number of the detection elements 31 is multiple, and the multiple detection elements 31 are arranged at intervals inside the measurement chamber 10. Specifically, the multiple detection elements 31 are arranged at intervals inside the measurement chamber 10, and the multiple measurement elements simultaneously feed the detected data back to the controller. The controller takes the average value of the pressures fed back by each detection element 31 and uses the average value of the pressures to correct the measurement mechanism 20, avoiding the influence of local pressure fluctuations inside the measurement chamber 10 on the measurement mechanism 20 and further improving the measurement accuracy.

[0050] It should be noted that when the number of the detection elements 31 is multiple, the multiple detection elements 31 are evenly distributed around the measurement mechanism 20, and a detection element 31 is also provided at the middle position of the detection mechanism, so as to effectively ensure the accuracy of the pressure data of the measurement mechanism 20, improve the accuracy of the correction of the measurement mechanism 20, and further improve the measured data.

[0051] Furthermore, the detection element 31 is a pressure sensor. Specifically, setting the detection element 31 as a pressure sensor can reduce the space occupied by the detection element 31 inside the measurement chamber 10, facilitate the installation of the detection element 31. In addition, the structure of the pressure sensor is simple and the cost is low, effectively reducing the manufacturing cost of the overlay measurement device 100. Moreover, the sensitivity of the pressure sensor is high, which can improve the accuracy of pressure data detection, and further ensure the correction effect on the measurement mechanism 20.

[0052] In other embodiments, the detection element 31 is a barometer, and the structure of the barometer is simple, further reducing the manufacturing cost of the overlay measurement device 100.

[0053] Furthermore, as Figure 1 shown, the measurement chamber 10 is provided with a connection structure 11, and the pipeline is matched with the connection structure 11 to communicate the gas source with the measurement chamber 10. Specifically, the connection structure 11 is disposed on the outer surface of the measurement chamber 10 and connected to the inside of the measurement chamber 10. When it is necessary to communicate the gas source with the measurement chamber 10, one end of the pipeline is matched with the connection structure 11, and the other end of the pipeline is then matched with the gas source. The overall structure is simple, facilitating the connection operation of the pipeline and effectively improving the assembly convenience of the overlay measurement device 100.

[0054] It should be pointed out that the connection structure 11 is usually a connector with a control valve. The connector is fixed on the outer surface of the measuring chamber 10 by welding or other means and is connected to the interior of the measuring chamber 10. When the control valve is opened, the connector is connected to the interior of the measuring chamber 10. When the control valve is closed, the connector is disconnected from the interior of the measuring chamber 10. The pipeline is connected and fixed to the connector by means of threads, quick-release structures, etc., so that the convenience of assembly is guaranteed.

[0055] Furthermore, the overlay measurement device 100 also includes a clamping member 40, which is movably arranged in the measurement chamber 10 and is used to support the wafer 200. Specifically, the clamping member 40 is arranged in the measurement chamber 10, and the clamping member 40 can move in the measurement chamber 10. When measuring the overlay mark 201 of the wafer 200, the wafer 200 is placed on the clamping member 40, and the clamping member 40 clamps the wafer 200, and the side of the wafer 200 with the overlay mark 201 is facing the measurement mechanism 20. By providing the clamping member 40, the position of the wafer 200 in the measurement chamber 10 is guaranteed. In addition, the movement of the clamping member 40 drives the movement of the wafer 200, thereby realizing the switching of the position of the wafer 200, so as to meet the measurement mechanism 20 to measure the overlay marks 201 at different positions, so that the measurement operation can be carried out effectively, thereby improving the efficiency of the measurement.

[0056] It should be pointed out that the clamping member 40 can be a structure such as a chuck, an electrostatic suction cup or a tray. When the wafer 200 is placed on the clamping member 40, the clamping member 40 can limit the wafer 200, thereby ensuring the position accuracy of the wafer 200, and further improving the accuracy of the measurement.

[0057] In addition, the overlay measurement device 100 also includes a driving member electrically connected to the controller, which can be a motor or a cylinder, etc. The driving member is connected to the chuck transmission. The controller controls the driving member, thereby realizing the driving of the chuck by the driving member, and then realizing the change of the position of the wafer 200, further ensuring the position switching requirement during the measurement of the overlay mark 201.

[0058] Furthermore, if Figure 1 As shown, the measuring mechanism 20 is an interferometer with a focusing system. Specifically, the focusing system is designed to measure the overlay mark 201 of the wafer 200 using the principle of interferometric imaging, effectively ensuring the accuracy of the measurement of the overlay mark 201, thereby effectively improving the accuracy of the measurement structure.

[0059] It should be pointed out that if Figure 1As shown, the interferometer includes an interference component 22 and a focusing component 21. Through the coordinated action of the interference component 22 and the focusing component 21, the measurement of the overlay mark 201 is achieved by utilizing the principle of light and shadow imaging. The interference component 22 includes a light source 221, a lens, a laser 222, and a reference signal detection unit 223. The focusing component 21 includes an objective lens 211, a first acquisition unit (CCD sensor) 212, a control unit (piezoelectric ceramic controller, PZT Controller) 213, an adjustment unit (piezoelectric ceramic actuator, PZT Actuator) 214, and a second acquisition unit (piezoelectric ceramic, PZT) 215.

[0060] The above description is merely 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 a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A lithography measurement device, characterized in that, The overlay measurement device includes: A measurement chamber for placing a wafer with overlay marks; A measurement mechanism disposed in the measurement chamber for measuring the overlay marks of the wafer; A regulation mechanism for regulating the temperature of the measurement chamber; The regulation mechanism includes: A gas source that is connected to the measurement chamber through a pipeline. The gas source is used to supply gas with a temperature to the measurement chamber to maintain the temperature of the measurement chamber at a preset temperature. The temperature of the gas stored in the gas source is higher than the temperature of the measurement chamber; A control component for turning on or off the pipeline; The measurement mechanism is an interferometer with a focusing system.

2. The overlay measurement device according to claim 1, wherein The preset temperature is 22 °C.

3. The overlay measurement device according to claim 1, characterized in that, The control component includes: A valve disposed on the pipeline; A controller electrically connected to the valve for controlling the opening and closing of the valve.

4. The overlay measurement device according to claim 3, wherein The control component further includes a detector disposed in the measurement chamber and electrically connected to the controller. The detector is used to collect the pressure of the measurement chamber.

5. The overlay measurement device according to claim 4, characterized in that, The number of the detectors is multiple, and the multiple detectors are arranged at intervals in the measurement chamber.

6. The overlay measurement device according to claim 4, characterized in that, The detector is a pressure sensor.

7. The overlay measurement device according to claim 1, wherein The measurement chamber is provided with a connection structure, and the pipeline cooperates with the connection structure to connect the gas source to the measurement chamber.

8. The overlay measurement device according to any one of claims 1 to 7, characterized in that The overlay measurement device further includes a clamping member movably disposed in the measurement chamber for supporting the wafer.

Images