Wide-range focusing and leveling device and method and focusing and leveling detection method

Abstract

The invention provides a wide-range focusing and leveling device, a wide-range focusing and leveling method and a focusing and leveling detection method. The wide-range focusing and leveling device comprises a focusing and leveling sensor, a moving table and a rapid deflection table. Parallel light emitted by the light source irradiates the projection slit plate, the projection imaging lens projects an image to a silicon wafer of the moving table, and the moving table is movably matched with the projection slit plate, so that a light beam passes through the projection slit plate and forms an expanded projection area on the silicon wafer along with the movement of the moving table; the detection imaging lens projects a silicon wafer surface image to the detection slit plate and the rapid deflection table through silicon wafer reflection along the propagation direction of light beams reflected by the surface of the silicon wafer, the rapid deflection table is used for changing the position of pattern imaging, and the detection slit plate is matched to project the pattern passing through the detection slit plate to the surface of a detector through the relay lens on a silicon wafer reflection light path; therefore, the detector detects the target position according to the light intensity signal to obtain the target range corresponding to the expanded projection area. And the detection range is greatly increased while the detection precision is ensured.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing, specifically to a large-range focusing and leveling device, method and focusing and leveling detection method. Background Art

[0002] Photolithography plays an important role in the field of semiconductor processing and manufacturing. With the development of photolithography technology, the numerical aperture of projection lenses has gradually increased, the depth of focus has continued to decrease, and the requirements for focusing and leveling sensors have become increasingly higher.

[0003] The basic working principle of the existing focusing and leveling sensor is triangulation distance measurement, which projects the slit pattern onto the surface of the silicon wafer, receives the corresponding detection slit plate, calculates the actual distance of the silicon wafer based on the light intensity signal obtained by detection, and realizes the deflection angle detection of the silicon wafer through multi-point detection. This solution can achieve nanometer-level detection accuracy, but the detection range is small.

[0004] Therefore, a new large-range focusing and leveling solution is needed. Summary of the invention

[0005] In view of this, the embodiments of the present specification provide a large-range focusing and leveling device, method, and focusing and leveling detection method.

[0006] The embodiments of this specification provide the following technical solutions:

[0007] The embodiment of this specification provides a large-range focusing and leveling device, including:

[0008] Light source, projection slit plate, projection imaging lens, motion stage, detection imaging lens, fast deflection stage, detection slit plate, relay lens, detector;

[0009] Wherein, along the propagation direction of the light beam projection silicon wafer surface, the parallel light emitted by the light source illuminates the projection slit plate, and the projection imaging lens projects the image onto the silicon wafer set on the moving stage. The moving stage can move and is used to cooperate with the projection slit plate, so that the light beam passes through the projection slit plate and forms an expanded projection area on the silicon wafer with the movement of the moving stage;

[0010] Along the propagation direction of the light beam reflected by the silicon wafer surface, after reflection from the silicon wafer, the detection imaging lens projects the image of the silicon wafer surface onto the detection slit plate. The fast tilting stage is used to change the position of the pattern imaging. In conjunction with the detection slit plate, the reflected light path of the silicon wafer is projected onto the detector surface via the relay lens, so that the detector can realize target position detection according to the light intensity signal to obtain the target range corresponding to the expanded projection area.

[0011] The embodiment of this specification also provides a large-range focusing and leveling method, using the large-range focusing and leveling device as described in the above technical revision, including:

[0012] The fast tilt table does not move, the motion table controls the detection target to move, the focusing and leveling sensors synchronously collect signals, and lock the distance between the silicon chip on the motion table and the zero plane of the focusing and leveling sensors;

[0013] After adjusting the motion stage to move the detection target to the zero plane position of the focusing and leveling sensor, the rapid tilting and tilting stage movement is started, and the target measuring range from the silicon wafer to the focusing and leveling sensor is obtained through the motion of the motion stage.

[0014] The embodiments of the present specification also provide a focusing and leveling detection method, which performs focusing and leveling detection after obtaining the target range by using the large-range focusing and leveling device as described in the above technical solution, or performs focusing and leveling detection after obtaining the target range by using the large-range focusing and leveling method as described in the above technical solution.

[0015] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification include at least:

[0016] This application designs a motion stage and a focusing and leveling sensor, which locks the target position by scanning over a large range, and then performs high-precision vertical position detection after the target moves into the detection range of the focusing and leveling sensor. This solution increases the detection range to the vertical movement range of the motion stage while ensuring high detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a schematic diagram of a focusing and leveling sensor structure provided in an embodiment of this specification;

[0019] Figure 2 is a schematic diagram of a slit plate provided in an embodiment of this specification;

[0020] Figure 3 This is the process of vertical detection provided by the embodiment of this specification Figure 1 ;

[0021] Figure 4 It is a schematic diagram of sampling data provided by the embodiments of this specification;

[0022] Figure 5 This is the process of vertical detection provided by the embodiment of this specification Figure 2 .

[0023] Among them, 1. light source, 2. projection slit plate, 3. projection imaging lens, 4. silicon wafer, 5. detection imaging lens, 5.1. fast deflection table, 6. detection slit plate, 7. relay lens, 8. detector, 9. motion table. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0028] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0029] The traditional focusing and leveling process utilizes the working principle of triangulation of the focusing and leveling sensor. Although it can achieve nanometer-level detection accuracy, the detection range is relatively small.

[0030] The prior art, such as the patent document with publication number CN105223780A, sets slits of various widths to increase the detection range, and realizes high-precision detection of a large range by using slits of various widths in combination. Although this solution increases the detection range, it can only be increased to the order of ten microns, in other words, the detection range is still small. In addition, the solution uses slits of various widths, which requires multiple adjustments in actual operation, making the detection process complicated and inconvenient.

[0031] Based on this, the embodiment of this specification proposes a new solution for large-range focusing and leveling: using a focusing and leveling sensor in combination with a motion stage, using the coordinated movement of the motion stage to lock the target position through a large-range scanning method, and performing high-precision vertical position detection after the movement enters the detection range of the focusing and leveling sensor. While ensuring high detection accuracy, the detection range is increased to the range corresponding to the vertical movement of the motion stage.

[0032] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0033] The embodiment of the present specification provides a large-range focusing and leveling device, which is provided with a movable motion stage 9 and a fast tilting stage 5.1. It also includes a focusing and leveling sensor, which includes a light source 1, a projection slit plate 2, a projection imaging lens 3, a detection imaging lens 5, a detection slit plate 6, a relay lens 7, and a detector 8.

[0034] like Figure 1 As shown, the light source emits parallel light to illuminate the projection slit plate, and the projection imaging lens projects the image onto the surface of the silicon wafer. The silicon wafer is mounted on a movable moving table. The movement of the moving table cooperates with the projection slit plate, so that the light beam passes through the projection slit plate and forms an expanded projection area on the silicon wafer as the moving table moves.

[0035] Along the propagation direction of the light beam reflected by the silicon wafer surface, after reflection from the silicon wafer, the detection imaging lens projects the image of the silicon wafer surface onto the detection slit plate. The fast tilting table is used to change the position of the pattern imaging. In conjunction with the detection slit plate, the reflected light path of the silicon wafer is projected onto the detector surface via the relay lens, and the detector realizes target position detection based on the light intensity signal to obtain the target range corresponding to the expanded projection area.

[0036] The target range is not only larger than the range of the focusing and leveling sensor itself, but also larger than the range of the prior art that can only be adjusted by slit plates of different widths. That is, while ensuring the detection accuracy, the detection range can be greatly increased.

[0037] Compared with the prior art which only uses slit plates of different widths to achieve a large range of ten microns, the large range and high precision focusing and leveling solution of the embodiment of this specification can increase the sensor detection range to the range of the motion stage.

[0038] In some embodiments, the motion stage moves vertically.

[0039] In some embodiments, the motion stage is divided into positive motion and negative motion. In some embodiments, the motion stage is divided into positive vertical motion and negative vertical motion.

[0040] In some embodiments, the motion stage sets a pre-scanning range, wherein the pre-scanning range enables the motion stage to drive the silicon wafer to move positively or negatively. The preset scanning range includes a vertical pre-scanning range, and the motion stage drives the silicon wafer to move positively or negatively according to the vertical pre-scanning range until the vertical position of the silicon wafer is near the zero plane of the focusing and leveling sensor. (That is, the intensity of the silicon wafer reflected signal received by the detector is the largest).

[0041] In some embodiments, the motion stage is combined with an interferometer or a grating ruler to obtain the movement amount. Specifically, an interferometer or a grating ruler is set for the motion stage, so that the movement amount of the motion stage is obtained through the interferometer or the grating ruler.

[0042] In some embodiments, the detection slit plate includes a precision detection slit plate or a detection slit plate with two different widths.

[0043] Specifically, in order to ensure the detection accuracy and increase the detection range during the focusing and leveling detection process, the slit images on the slit plate are designed to have different widths. The wider slit is used for rough detection, and the narrower slit is used for fine detection. In the prior art, in order to increase the detection range, even if more wider slits of different widths are set for the wider slit, the increased range is very limited and can only be increased to the order of ten microns; in this way, the increased range using the narrower slit is very small.

[0044] By utilizing the large-range focusing and leveling solution of the present application and cooperating with the motion stage, only the precision detection slit can be used to achieve a large-range amplification for the precision detection process while ensuring the detection accuracy.

[0045] In some embodiments, only two-level width detection slits may be used in conjunction with the motion stage to achieve large-scale amplification, thereby ensuring detection accuracy while reducing adjustments in actual operations and improving convenience.

[0046] In some embodiments, the projection slit plate 2 and the detection slit plate 6 are structured as follows: Figure 2 As shown, a 5×7 array slit is used, and each slit has the same width. The slit width determines the detection range of the focusing and leveling sensor.

[0047] In combination with the above embodiments, the large-range focusing and leveling method of the embodiments of this specification uses the large-range focusing and leveling device as mentioned above, the rapid tilt table does not move, the motion table controls the detection target to move, the focusing and leveling sensor synchronously collects signals, and locks the distance between the silicon wafer on the motion table and the zero plane of the focusing and leveling sensor; after adjusting the motion table to move the detection target to the zero plane position of the focusing and leveling sensor, the rapid tilt table movement is started, and the target range from the silicon wafer to the focusing and leveling sensor is obtained through the movement of the motion table.

[0048] That is Figure 3 As shown, through the large-range scanning of the moving stage, the distance between the silicon wafer on the moving stage and the zero plane of the focusing and leveling sensor is locked, and then the target range from the silicon wafer to the focusing and leveling sensor is obtained by adjusting the fast tilt table in conjunction with the moving stage.

[0049] In some embodiments, by analyzing the sampling information, the position of the maximum signal is obtained, that is, the position where the target is in the zero plane of the focus and leveling sensor during the scanning process. Specifically, the focus and leveling sensor synchronously collects signals, and the sampling obtains the signal such as Figure 4 The signal is obtained by analyzing the sampling, and the position of the maximum signal is the position where the target is in the zero plane of the focusing and leveling sensor during the scanning process. Figure 4 The signal shows that when the motion stage moves to the 0 position, the target is at the zero plane position of the focus and leveling sensor.

[0050] The motion table can perform positive motion such as upward motion relative to the zero plane position, and can also perform negative motion such as downward motion.

[0051] Specifically, during the process of locking the zero plane of the silicon chip on the moving stage relative to the focusing and leveling sensor, the fast tilting stage is not started, that is, the fast tilting stage does not move. After locking the zero plane position of the focusing and leveling sensor, the fast tilting stage is started to move.

[0052] The large-range focusing and leveling method also includes: obtaining a part of the target range by performing positive movement of the moving stage relative to the zero plane; the moving stage performs negative movement relative to the zero plane, and if it moves to the maximum position in the negative direction and the signal obtained by analyzing the focusing and leveling sensor is an invalid signal, the current moving stage is moved forward relative to the zero plane until a valid signal is collected to obtain another part of the target range; wherein the positive movement range is the range of the focusing and leveling sensor itself, such as A.

[0053] Specific as Figure 3 and Figure 5 As shown, during the process of locking the zero plane, the fast tilting table 5.1 does not move, the moving table 9 controls the detection target to move vertically, and the focusing and leveling sensors synchronously collect signals, and the sampling signals are as follows: Figure 4The signal is obtained by analyzing the sampling, and the position of the maximum signal is the position where the target is in the zero plane of the focusing and leveling sensor during the scanning process. Figure 4 The signal shows that the target is at the zero plane position of the focus and leveling sensor when the motion stage moves to the 0 position. The target is moved to the zero plane position of the focus and leveling sensor according to the detection result.

[0054] Then the fast tilting table 5.1 is started to perform position detection; finally, a part of the target measuring range is obtained.

[0055] Or, start the fast tilt table 5.1, and move the motion table 9 to the maximum position in the negative direction; sample the focus and leveling sensor to obtain a signal; analyze whether the obtained signal is a valid signal, if it is an invalid signal, the motion table moves forward A, A is the range of the focus and leveling sensor itself; repeat the above sampling and analysis process until a valid signal is collected; finally, another part of the target range is obtained.

[0056] Compared with the negative movement of the motion platform, it is easier to obtain valid signals in positive movement, so the collected signals are usually valid signals. However, if the signal obtained by analysis and collection is an invalid signal, similarly, the motion platform moves in the negative direction A, that is, the motion platform does not exceed the range of the focusing and leveling sensor itself to quickly locate, etc. The specific process will not be repeated here.

[0057] In some embodiments, the target vertical position is obtained by adding the moving position of the motion stage to the position calculated during the focusing and leveling process;

[0058] The target range is obtained by counting the range of the target vertical position.

[0059] Specifically, no matter the motion stage moves positively or negatively, the vertical position of the target is obtained by adding the current motion stage position to the position calculated by the focusing and leveling sensors, and the vertical position of the target obtained by the positive and negative motions of the motion stage is statistically analyzed, that is, the two parts of the target range are added and statistically analyzed, that is, the expanded target range is obtained. In this way, the high-precision detection of the vertical position of the target is completed.

[0060] In combination with the above embodiments, the embodiments of this specification also provide a focusing and leveling detection method, which performs focusing and leveling detection after obtaining the target range by using the large-range focusing and leveling device described in any one of the above technical schemes, or performs focusing and leveling detection after obtaining the target range by using the large-range focusing and leveling method described in the above technical scheme.

[0061] This application combines a motion stage and a focusing and leveling sensor to lock the target position through a large-range scanning method, and then conducts high-precision vertical position detection after the movement enters the detection range of the focusing and leveling sensor. This solution increases the detection range to the vertical movement range of the motion stage while ensuring high detection accuracy.

[0062] The same or similar parts between the various embodiments in this specification can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the product embodiment described later, since it corresponds to the method, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment.

[0063] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A large-range focusing and leveling device, characterized in that: include: Light source, projection slit plate, projection imaging lens, motion stage, detection imaging lens, fast deflection stage, detection slit plate, relay lens, detector; Wherein, along the propagation direction of the light beam projection silicon wafer surface, the parallel light emitted by the light source illuminates the projection slit plate, and the projection imaging lens projects the image onto the silicon wafer set on the moving stage. The moving stage can move and is used to cooperate with the projection slit plate, so that the light beam passes through the projection slit plate and forms an expanded projection area on the silicon wafer with the movement of the moving stage; Along the propagation direction of the light beam reflected by the silicon wafer surface, after reflection from the silicon wafer, the detection imaging lens projects the image of the silicon wafer surface onto the detection slit plate. The fast tilting stage is used to change the position of the pattern imaging. In conjunction with the detection slit plate, the reflected light path of the silicon wafer is projected onto the detector surface via the relay lens, so that the detector can realize target position detection according to the light intensity signal to obtain the target range corresponding to the expanded projection area.

2. The large-range focusing and leveling device according to claim 1, characterized in that: The moving platform moves vertically.

3. The large-range focusing and leveling device according to claim 2, characterized in that: The motion platform is divided into positive motion and negative motion.

4. The large-range focusing and leveling device according to claim 1, characterized in that: The moving stage is provided with a pre-scanning range, wherein the pre-scanning range enables the moving stage to drive the silicon wafer to move in a positive direction or a negative direction.

5. The large-range focusing and leveling device according to claim 1, characterized in that: The motion stage is combined with an interferometer or a grating ruler to obtain the movement amount.

6. The large-range focusing and leveling device according to claim 1, characterized in that: The detection slit plate includes a precise detection slit plate or a detection slit plate with two different widths.

7. A large-range focusing and leveling method, characterized in that: The large-range focusing and leveling device according to any one of claims 1 to 6 comprises: The fast tilt table does not move, the motion table controls the detection target to move, the focusing and leveling sensors synchronously collect signals, and lock the distance between the silicon chip on the motion table and the zero plane of the focusing and leveling sensors; After adjusting the motion stage to move the detection target to the zero plane position of the focusing and leveling sensor, the rapid tilting and tilting stage movement is started, and the target measuring range from the silicon wafer to the focusing and leveling sensor is obtained through the motion of the motion stage.

8. The large-range focusing and leveling method according to claim 7, characterized in that: By analyzing the sampling information, the position of the maximum signal is obtained, which is the position where the target is in the zero plane of the focusing and leveling sensor during the scanning process; The large-range focusing and leveling method further includes: obtaining a portion of the target range by performing positive movement of the motion stage relative to the zero plane; Or the motion stage moves negatively relative to the zero plane. If it moves to the maximum position in the negative direction and the signal obtained by the focus and leveling sensor analysis is an invalid signal, the current motion stage moves positively relative to the zero plane until a valid signal is collected to obtain another part of the target range; the positive motion range is the range of the focus and leveling sensor itself.

9. The large-range focusing and leveling method according to claim 7, characterized in that: Also includes: The vertical position of the target is obtained by adding the moving position of the motion stage to the position calculated during the focusing and leveling process; The target range is obtained by counting the range of the target vertical position.

10. A focusing and leveling detection method, characterized in that: A focusing and leveling test is performed after obtaining the target range by using the large-range focusing and leveling device as described in any one of claims 1 to 6, or a focusing and leveling test is performed after obtaining the target range by using the large-range focusing and leveling method as described in claim 7, 8 or 9.

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