Film thickness distribution measuring apparatus and film thickness distribution measuring method

Abstract

To provide a film thickness distribution measuring apparatus and a film thickness distribution measuring method for measuring the film thickness distribution across the entire wafer surface which are capable of measuring the film thickness distribution in an outer peripheral region, in which film thickness variation is large, with high spatial resolution and high accuracy, while suppressing both a decrease in the throughput and an increase in the volume of measurement data.SOLUTION: A film thickness distribution measuring apparatus for measuring the film thickness distribution of a film formed on the surface of a wafer comprises: a wafer entire-surface measurement system configured to measure the film thickness distribution across the entire surface of the wafer; and a wafer outer periphery measurement system configured to measure the film thickness distribution only in the outer periphery of the wafer excluding the center. The wafer entire-surface measurement system and the wafer outer periphery measurement system can be set different in the spatial resolution. A measuring method employing the film thickness distribution measuring apparatus is also provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film thickness distribution measuring device and a film thickness distribution measuring method. [Background technology]

[0002] In the manufacture of semiconductor devices such as integrated circuit devices, multiple chips (DIE) are formed on a semiconductor substrate (wafer). The more chips that can be obtained from one wafer, the higher the yield, which leads to cost reduction. One of the factors that influences the number of chips that can be obtained from one wafer is the number of effective chips on the periphery of the wafer. The periphery of the wafer is prone to defective chips due to the presence of defect factors such as uneven thickness of the film provided on the wafer (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-208212 A [Patent Document 2] JP 2017-146288 A [Patent Document 3] JP 2015-017804 A [Patent Document 4] JP 2013-137205 A [Patent Document 5] JP 2000-314612 A [Non-patent literature]

[0004] [Non-Patent Document 1] K. Nakazawa et. al., 3D Sequential Process Integration for CMOS Image Sensor, 2021 IEEE International Electron Devices Meeting (IEDM), 653-656, 09 March 2022 [Non-Patent Document 2] Eric Beyne et. al., Nano-Through Silicon Vias (nTSV) for Backside Power Delivery Networks (BSPDN), 2023 Symposium on VLSI Technology and Circuits Digest of Technical Papers, 1-2, 24 July 2023 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to manufacture high-quality devices with high yields, it is necessary to measure and evaluate the film thickness distribution of a film provided on a wafer over the entire surface. In the device manufacturing process, in order to suppress a decrease in device yields due to changes in film thickness at the wafer's periphery (Patent Document 1), it is particularly important to adjust the film thickness of such an area more accurately. In order to adjust the film thickness of such an area of ​​the wafer, it is necessary to measure the film thickness distribution at the wafer's periphery with high spatial resolution and high accuracy to grasp the film thickness distribution. In particular, in order to suppress defects in chips (DIE) at the periphery of the wafer and improve yields, such as 3D devices formed by stacking such as wafer bonding, CMOS (Complementary Metal Oxide Semiconductor) image sensors (see Non-Patent Document 1), and Si layers in backside power delivery networks (BSPDN: Backside Power Delivery Network for transistors, see Non-Patent Document 2), which have been attracting attention in recent years, it is becoming increasingly important to measure the film thickness distribution at the periphery with high accuracy.

[0006] Many devices and methods for measuring the thickness distribution of a film formed on a wafer have been proposed (e.g., Patent Documents 2 to 5). However, when measuring the entire surface of a wafer with high spatial resolution using conventional measuring devices, there are problems such as a decrease in throughput and large data that is difficult to handle.

[0007] Therefore, the object is to provide a film thickness distribution measuring device and a film thickness distribution measuring method that can suppress a decrease in throughput and an increase in the amount of measurement data when measuring the film thickness distribution over the entire wafer, and that can measure the film thickness distribution in the outer periphery, where the film thickness changes greatly, with high spatial resolution and high accuracy. [Means for solving the problem]

[0008] The present invention has been made to achieve the above-mentioned object, and provides a film thickness distribution measuring device for measuring the film thickness distribution of a film formed on a surface of a wafer, the film thickness distribution measuring device comprising an entire surface of the wafer measurement system for measuring the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system for measuring the film thickness distribution only in the outer periphery of the surface of the wafer excluding the central portion, the wafer outer periphery measurement system and the entire surface of the wafer measurement system being set to different spatial resolutions.

[0009] Such a film thickness distribution measuring device is capable of measuring with different resolution depending on the region of the entire surface and the outer periphery of the wafer, so that when measuring the film thickness distribution over the entire surface of the wafer, it is possible to perform film thickness measurement at the outer periphery of the wafer where the film thickness varies greatly with high spatial resolution and high accuracy, and is a film thickness distribution measuring device that can suppress a decrease in throughput and an increase in the amount of measurement data.Furthermore, the footprint (the area occupied by the device installation) of the film thickness distribution measuring device is not increased.

[0010] In this case, the film thickness distribution measuring device may include a parallel direction drive unit that moves the entire wafer surface measuring system and the wafer relatively in parallel in the surface direction of the wafer.

[0011] This makes it possible to measure the film thickness distribution over the entire surface using a simpler XY coordinate system, and reduces the amount of measurement data.

[0012] In this case, the film thickness distribution measuring device may include a rotation direction drive unit that relatively rotates the wafer outer periphery measuring system and the wafer about the center of the wafer as an axis.

[0013] This makes it possible to more easily measure the film thickness distribution only in the peripheral portion of the wafer, where this is required.

[0014] In this case, the film thickness distribution measuring device may be provided with a rotatable wafer placement portion on which the wafer is placed.

[0015] This makes it easier to simultaneously measure the entire surface and only the outer periphery of the wafer, thereby increasing throughput. In addition, the structure of the device can be simplified because the measurement can be performed using only the rotation drive system.

[0016] In this case, the wafer overall surface measuring system and the wafer outer periphery measuring system may be a film thickness distribution measuring apparatus equipped with a line optical system.

[0017] This makes it possible to measure the film thickness distribution over the entire surface and the outer periphery of the wafer with higher density, higher accuracy, shorter time, and higher throughput.

[0018] The present invention also provides a film thickness distribution measurement method for measuring the film thickness distribution of a film formed on the surface of a wafer using a film thickness distribution measurement device that includes an entire surface of a wafer measurement system that measures the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system that measures the film thickness distribution only in the outer periphery of the wafer surface excluding the central portion, and that can set the wafer outer periphery measurement system and the entire surface of the wafer measurement system to different spatial resolutions, in which the film thickness distribution is measured over the entire surface of the wafer using the entire surface of the wafer, and the film thickness distribution is measured only in the outer periphery of the wafer surface excluding the central portion using the wafer outer periphery measurement system with a spatial resolution higher than that of the entire surface of the wafer measurement system.

[0019] According to this film thickness distribution measurement method, when measuring the film thickness distribution over the entire wafer, it is possible to measure the film thickness distribution on the outer periphery of the wafer, where the film thickness varies greatly, with high spatial resolution and high accuracy, while suppressing a decrease in throughput and an increase in the amount of measurement data.

[0020] In this case, the method may be a film thickness distribution measuring method in which the film thickness distribution is measured over the entire surface of the wafer while the entire surface measuring system and the wafer are moved relatively in parallel in the surface direction of the wafer.

[0021] This makes it possible to measure the film thickness distribution over the entire surface using a simpler XY coordinate system, and reduces the amount of measurement data.

[0022] In this case, the wafer outer periphery measurement system and the wafer can be rotated relatively around the center of the wafer as an axis, and the film thickness distribution can be measured only on the outer periphery of the surface of the wafer, excluding the central portion.

[0023] This makes it possible to more simply measure the film thickness distribution only in the peripheral portion of the wafer, where this is required.

[0024] In this case, the film thickness distribution may be measured by the wafer entire surface measurement system and the wafer outer periphery measurement system while rotating the wafer.

[0025] This makes it easier to simultaneously measure the entire surface and only the outer periphery of the wafer, thereby increasing throughput. In addition, the structure of the device can be simplified because the measurement can be performed using only the rotation drive system.

[0026] In this case, the method may be such that the wafer overall surface measuring system and the wafer outer periphery measuring system are equipped with line optical systems.

[0027] This makes it possible to measure the film thickness distribution over the entire surface and the outer periphery of the wafer with higher density, higher accuracy, shorter time, and higher throughput. Effect of the Invention

[0028] As described above, the film thickness distribution measuring device of the present invention is capable of measuring with different resolution depending on the region of the entire surface and the outer periphery of the wafer, and therefore, when measuring the film thickness distribution over the entire surface of the wafer, it is possible to perform film thickness measurement at the outer periphery of the wafer where the film thickness varies greatly with high spatial resolution and high accuracy, thereby providing a film thickness distribution measuring device that can suppress a decrease in throughput and an increase in the amount of measurement data, and also does not increase the footprint of the film thickness distribution measuring device.

[0029] According to the film thickness distribution measuring method of the present invention, when measuring the film thickness distribution over the entire wafer, it is possible to perform film thickness distribution measurement with high accuracy and the required high spatial resolution only for the outer periphery of the wafer where the film thickness changes greatly, while suppressing a decrease in throughput and an increase in the amount of measurement data. [Brief description of the drawings]

[0030] [Figure 1] 1 shows a conceptual diagram illustrating an example of a film thickness distribution measuring device according to the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a line optical system. [Diagram 3] A specific example of film thickness distribution measurement using a wafer entire surface measurement system and a wafer outer periphery measurement system in the film thickness distribution measurement apparatus according to the present invention will be described. [Figure 4] FIG. 13 is a diagram illustrating the film thickness distribution measurement results of a comparative example. [Diagram 5] FIG. 13 is a diagram illustrating the film thickness distribution measurement results of the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will be described in detail below, but the present invention is not limited thereto.

[0032] As described above, there has been a demand for a film thickness distribution measuring device and a film thickness distribution measuring method that can suppress a decrease in throughput and an increase in the amount of measurement data when measuring the film thickness distribution over the entire wafer, and that can measure the film thickness distribution in the outer periphery, where the film thickness changes greatly, with high spatial resolution and high accuracy.

[0033] As a result of intensive investigations into the above-mentioned problems, the inventors have discovered a film thickness distribution measuring device for measuring the film thickness distribution of a film formed on the surface of a wafer, the film thickness distribution measuring device comprising an entire surface of the wafer measurement system for measuring the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system for measuring the film thickness distribution only in the outer periphery of the wafer excluding the central portion, the wafer outer periphery measurement system and the entire surface of the wafer measurement system being capable of being set to different spatial resolutions. This film thickness distribution measuring device enables measurements with different resolutions depending on the entire surface and outer periphery of the wafer without increasing the footprint of the film thickness distribution measuring device, and therefore makes it possible to measure the film thickness of the outer periphery of the wafer, where the film thickness varies greatly, with high spatial resolution and with high accuracy when measuring the film thickness distribution over the entire surface of the wafer, and thereby suppresses a decrease in throughput, an increase in measurement data, and an increase in footprint, and has completed the present invention.

[0034] The inventors have also discovered that a film thickness distribution measurement method for measuring the film thickness distribution of a film formed on the surface of a wafer using a film thickness distribution measurement device that includes an entire surface of the wafer measurement system that measures the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system that measures the film thickness distribution only in the outer periphery of the wafer excluding the central portion of the wafer, and that can set the wafer outer periphery measurement system and the entire surface of the wafer measurement system to different spatial resolutions, wherein the film thickness distribution measurement method uses the entire surface of the wafer measurement system to measure the film thickness distribution over the entire surface of the wafer, and uses the wafer outer periphery measurement system to measure the film thickness distribution only in the outer periphery of the wafer excluding the central portion of the wafer with a spatial resolution higher than that of the entire surface of the wafer measurement system, and that when measuring the film thickness distribution over the entire surface of the wafer, it is possible to perform film thickness measurement of the outer periphery of the wafer, where film thickness changes greatly, with high spatial resolution and high accuracy while suppressing a decrease in throughput and an increase in measurement data, and have completed the present invention.

[0035] The following description will be given with reference to the drawings.

[0036] [Film thickness distribution measuring device] First, the film thickness distribution measuring device according to the present invention will be described. FIG. 1 is a conceptual diagram showing an example of the film thickness distribution measuring device according to the present invention. The film thickness distribution measuring device 100 according to the present invention is for measuring the film thickness distribution of a film F formed on the surface of a wafer W, and as shown in FIG. 1, includes an entire wafer measuring system 1 for measuring the film thickness distribution over the entire surface of the wafer W, and a wafer outer peripheral measuring system 2 for measuring the film thickness distribution only in the outer peripheral portion excluding the center portion of the surface of the wafer W. The film F formed on the surface of the wafer W may be a single layer (single layer film) or a multilayer film of two or more layers. The range of the outer peripheral portion excluding the center portion of the surface of the wafer W is not particularly limited, and can be appropriately set according to the diameter of the wafer W and the film thickness distribution characteristics of the film F. For example, it can be a region of 10 mm, 20 mm, or 30 mm radially inward from the edge (outer peripheral end) of the wafer.

[0037] In addition, the wafer outer periphery measurement system 2 and the wafer entire surface measurement system 1 can be set to different spatial resolutions. As such, at least one of the wafer outer periphery measurement system 2 and the wafer entire surface measurement system 1 may be capable of adjusting and setting the spatial resolution independently of the other.

[0038] The film thickness distribution measuring apparatus 100 according to the present invention is capable of changing the spatial resolution (accuracy) depending on the region of the entire surface and the outer periphery of the wafer W, and therefore, when measuring the film thickness distribution over the entire surface of the wafer, the spatial resolution is set so as to perform film thickness measurement at the outer periphery of the wafer, where the film thickness varies greatly, with high spatial resolution and high accuracy, thereby preventing a decrease in throughput and an increase in the amount of measurement data. In addition, the film thickness distribution measuring apparatus according to the present invention is provided with two measurement systems in one film thickness distribution measuring apparatus, and therefore does not increase the footprint of the measuring apparatus.

[0039] In the film thickness distribution measuring apparatus 100, as shown in FIG. 1, the entire wafer measurement system 1 and the wafer outer periphery measurement system 2 may be disposed above a wafer mounting part 5 in one measurement chamber, and the entire wafer measurement and the wafer outer periphery measurement may be performed sequentially or simultaneously on the wafer W mounted on the wafer mounting part 5.

[0040] Also, a single measurement chamber may have multiple wafer placement parts 5, with only the entire wafer measurement system 1 arranged on one wafer placement part, and only the wafer outer periphery measurement system 2 arranged on the other wafer placement parts. Furthermore, a single measurement chamber may have an aligner that positions the wafer placement part 5 and the wafer, with measurement by the entire wafer measurement system 1 performed on the wafer placement part 5, and measurement by the wafer outer periphery measurement system 2 performed on the aligner. In this manner, multiple wafers can be measured simultaneously in parallel.

[0041] Furthermore, in the film thickness distribution measuring device according to the present invention, multiple measurement chambers may be provided, one of which may house only the entire wafer measurement system 1, and the other may house only the wafer outer periphery measurement system 2, and the transfer system may be shared. Even in this case, multiple wafers can be measured simultaneously in parallel.

[0042] (Wafer full surface measurement system) Next, the entire wafer surface measuring system 1 will be described. The entire wafer surface measuring system 1 according to the present invention is not particularly limited as long as it measures the film thickness distribution on the entire wafer surface. The measuring method (measuring means) is also not particularly limited, and may be a spectroscopic ellipsometry method or a reflectance spectroscopy method. It is particularly preferable that the entire wafer surface measuring system 1 according to the present invention is equipped with a line optical system. With such a system, it is possible to perform measurements with higher density and higher accuracy in a shorter time. The line optical system will be described in detail later.

[0043] (Wafer outer circumference measurement system) Next, the wafer outer periphery measurement system 2 will be described. The wafer outer periphery measurement system 2 according to the present invention is not particularly limited as long as it measures the film thickness distribution of the wafer outer periphery. The measurement method (measurement means) is also not particularly limited, and may be a spectroscopic ellipsometry method or a reflectance spectroscopy method. The wafer outer periphery measurement system 2 is not limited to one, and may be provided with a plurality of systems. It is also preferable that the wafer outer periphery measurement system 2 according to the present invention is provided with a line optical system. With such a system, it is possible to perform measurements with higher density and higher accuracy in a shorter time. The line optical system will be described in detail later.

[0044] (Parallel drive unit) The film thickness distribution measuring device 100 according to the present invention may include a parallel direction driving unit 3. The parallel direction driving unit 3 moves the entire surface of the wafer measuring system 1 and the wafer W relatively in parallel in the surface direction of the wafer W. This makes it possible to more easily measure the film thickness distribution over the entire surface of the wafer. FIG. 1 shows a form in which the parallel direction driving unit 3 moves the entire surface of the wafer measuring system 1 in parallel with respect to the wafer W, but the parallel direction driving unit 3 may move the wafer W in parallel with respect to the entire surface of the wafer measuring system 1, or may be capable of moving each (both) of the wafer W and the entire surface of the wafer measuring system 1.

[0045] (Rotational direction drive unit) The film thickness distribution measuring device 100 according to the present invention may include a rotation direction drive unit 4. The rotation direction drive unit 4 rotates the wafer outer periphery measuring system 2 and the wafer W relatively around the center of the wafer W as an axis. This makes it possible to more easily measure the film thickness distribution of the wafer outer periphery. Although FIG. 1 shows a form in which the wafer outer periphery measuring system 2 is rotated relative to the wafer W, the rotation direction drive unit 4' may rotate the wafer W relative to the wafer outer periphery measuring system 2, or each (both) of the wafer W and the wafer outer periphery measuring system 2 may be rotatable.

[0046] (Wafer placement section) The film thickness distribution measuring device 100 according to the present invention may include a rotatable wafer mounting part 5 on which a wafer W is mounted. By using the film thickness distribution measuring device 100 including such a wafer mounting part 5, the film thickness distribution can be measured simultaneously by the entire wafer measurement system 1 and the wafer outer periphery measurement system 2 by rotating the wafer. This results in a film thickness distribution measuring device that can measure the film thickness distribution in a shorter time. The wafer mounting part 5 according to the present invention may also include the above-mentioned rotation direction drive part 4'.

[0047] (Line optical system) The entire wafer surface measuring system 1 and the wafer outer periphery measuring system 2 according to the present invention preferably include a line optical system as described above.

[0048] An example of the line optical system will be described with reference to FIG. 2. FIG. 2 is a diagram for explaining the line optical system of the entire wafer measuring system. As shown in FIG. 2, the line optical system 6 irradiates a line-shaped light L1 from a line light source 10 onto a film on the wafer W at an incident angle θ. Then, the line-shaped light reflected from the surface of the wafer W is detected by a detector 13 and subjected to spectrum analysis, thereby making it possible to measure the film thickness (distribution) on one line. Note that, although FIG. 2 is a diagram for explaining an example of the line optical system of the entire wafer measuring system 1, the measurement principle is the same even when the line optical system is provided in the wafer outer periphery measuring system 2.

[0049] If the entire wafer surface measurement system 1 and the wafer peripheral portion measurement system 2 are equipped with a line optical system, it becomes possible to measure the film thickness distribution with higher density and with higher accuracy in a shorter time.

[0050] In particular, if the entire wafer surface measurement system 1 and the wafer outer periphery measurement system 2 are equipped with a line optical system 6 and are equipped with a parallel direction drive unit 3 and / or a rotational direction drive unit 4, or are equipped with a wafer mounting unit 5 that can be freely rotated by a rotational direction drive unit 4', then it becomes possible to more easily measure the film thickness distribution over the entire wafer surface and outer periphery and, as a result, it becomes possible to more easily measure the film thickness distribution over a shorter period of time with higher density and with higher accuracy using the line optical system 6.

[0051] (others) In addition, the film thickness distribution measuring device according to the present invention may be one in which each part and / or the whole device are controlled by a control part (not shown). In the wafer full surface measuring system and the wafer outer periphery measuring system, an appropriate lens can be selected according to the camera and the object to be measured.

[0052] Next, a film thickness distribution measuring apparatus according to the present invention will be described with reference to FIG. 3, with reference to an example of a combination of the entire wafer surface measuring system 1 and the wafer outer periphery measuring system 2. FIG.

[0053] In the example of FIG. 3(A), the entire wafer measurement system measures the film thickness distribution over the entire wafer surface by irradiating a line-shaped light L1 that covers the entire range in the diameter direction of the wafer W. The outer periphery wafer measurement system irradiates a line-shaped light L2 that covers the outer periphery of the wafer W to measure the film thickness distribution over the outer periphery of the wafer with higher spatial resolution (higher accuracy) than the measurement by the entire wafer measurement system. By rotating the wafer W, the entire wafer measurement system and the outer periphery wafer measurement system measure the film thickness distribution over the entire wafer W and the outer periphery of the wafer. In the example shown in FIG. 3(A), the film thickness distribution measuring device is configured to irradiate a line-shaped light L2 at two different locations as two wafer outer periphery measurement systems, and the film thickness distribution over the entire wafer W surface can be measured by simply rotating the wafer W halfway.

[0054] In the example of Fig. 3(B), the full wafer measurement system measures the film thickness distribution over the entire wafer surface by irradiating a line-shaped light L1 that covers a range equivalent to the radius of the wafer W. In addition, the wafer outer periphery measurement system measures the film thickness distribution over the wafer outer periphery with higher spatial resolution (higher accuracy) than the measurement by the full wafer measurement system by irradiating a line-shaped light L2 that covers the outer periphery of the wafer W. In the example shown in Fig. 3(B), the film thickness distribution over the entire surface of the wafer W can be measured by rotating the wafer W once.

[0055] In the example of Figure 3(C), the full wafer measurement system measures the film thickness distribution over the entire wafer surface by irradiating a line-shaped light L1 that covers the entire diameter range of the wafer W. In addition, the wafer outer periphery measurement system irradiates a line-shaped light L2 that covers the outer periphery of the wafer W to measure the film thickness distribution on the outer periphery of the wafer with higher spatial resolution (higher accuracy) than the measurement by the full wafer measurement system. The film thickness distribution over the entire wafer W is measured by moving the wafer W in parallel (linearly) relative to the full wafer measurement system. In addition, the wafer W is rotated to measure the film thickness distribution on the outer periphery of the wafer W by the wafer outer periphery measurement system.

[0056] As described above, the measurement using the entire wafer measurement system and the measurement using the wafer outer periphery measurement system can be performed at different locations. In this case, the parallel direction drive unit and the rotation direction drive unit described above can be appropriately combined and used for driving the measurement using the entire wafer measurement system and the measurement using the wafer outer periphery measurement system.

[0057] In addition to the above example, the wafer entire surface measuring system may use obliquely incident measuring light, and the wafer outer periphery measuring system may use perpendicularly incident measuring light.

[0058] [Thickness distribution measurement method] Next, a thickness distribution measuring method according to the present invention will be described. Note that the description of the thickness distribution measuring apparatus according to the present invention may be omitted as appropriate.

[0059] The film thickness distribution measuring method according to the present invention is a film thickness distribution measuring method for measuring the film thickness distribution of a film F formed on the surface of a wafer W using the film thickness distribution measuring device according to the present invention described above. The film thickness distribution is measured over the entire surface of the wafer W using the entire wafer measurement system 1, and the film thickness distribution is measured only on the outer periphery of the surface of the wafer W excluding the central part with a spatial resolution higher than that of the entire wafer measurement system 1 using the wafer outer periphery measurement system 2. According to the film thickness distribution measuring method according to the present invention, when measuring the film thickness distribution over the entire wafer, the film thickness measurement of the outer periphery of the wafer where the film thickness varies greatly can be performed with high spatial resolution and high accuracy while suppressing a decrease in throughput and an increase in the measurement data. The film thickness distribution data of the central part of the wafer where the film thickness variation is relatively small is obtained using the film thickness distribution measurement result using the entire wafer measurement system 1, and the film thickness distribution data of the outer periphery of the wafer where the film thickness distribution tends to change rapidly and requires measurement with higher accuracy is obtained using the film thickness distribution measurement result using the wafer outer periphery measurement system 2, so that the film thickness distribution of the film formed on the wafer can be evaluated.

[0060] The film F formed on the surface of the wafer W to be measured by the film thickness distribution measuring method according to the present invention is not particularly limited. It may be any film, such as a film formed on the wafer W by a gas phase reaction or the like, a film formed by applying a resist layer or the like, a film in which the surface of the wafer W is chemically converted by oxidation, nitridation, or the like, an SOI layer of an SOI wafer, a BOX layer, etc. Also, the wafer W to be measured may be not only a single-layer film, but also a multilayer film having two or more layers.

[0061] At this time, it is preferable to measure the film thickness distribution over the entire surface of the wafer W while relatively translating the entire surface measurement system 1 and the wafer W in the surface direction of the wafer W. This makes it easier to measure the film thickness distribution over the entire surface of the wafer.

[0062] It is also preferable to measure the film thickness distribution only on the outer periphery of the surface of the wafer W, excluding the central part, while rotating the wafer outer periphery measurement system 2 and the wafer W relatively around the center of the wafer W. This makes it easier to measure the film thickness distribution on the outer periphery of the wafer.

[0063] It is also preferable to measure the film thickness distribution by the entire wafer surface measurement system 1 and the wafer outer periphery measurement system 2 while rotating the wafer W. This makes it possible to measure the film thickness distribution over the entire wafer surface and the outer periphery in a shorter time.

[0064] It is also preferable to use a system equipped with a line optical system 6 as the entire wafer surface measuring system 1 and the wafer peripheral portion measuring system 2. This makes it possible to perform measurements with higher density and higher accuracy in a shorter time.

[0065] In particular, by using an entire wafer surface measurement system 1 and a wafer outer periphery measurement system 2 equipped with a line optical system 6, and measuring the film thickness distribution over the entire surface of the wafer W while moving the entire wafer surface measurement system 1 and the wafer W relatively in parallel in the surface direction of the wafer W, and / or by rotating the wafer outer periphery measurement system 2 and the wafer W relatively around the center of the wafer W as an axis to measure the film thickness distribution only on the outer periphery of the surface of the wafer W excluding the central portion, or by measuring the film thickness distribution by the entire wafer surface measurement system 1 and the wafer outer periphery measurement system 2 while rotating the wafer W, it is possible to obtain a higher density and more accurate film thickness distribution measurement in a shorter time than when the line optical system 6 is used, and to more simply measure the film thickness distribution over the entire wafer and / or the outer periphery. This makes it possible to more simply and quickly obtain a higher density and more accurate film thickness distribution measurement. EXAMPLES

[0066] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[0067] (Example) The thickness distribution of a Si film formed on a silicon wafer with a diameter of 300 mm was evaluated. Using the thickness distribution measurement device shown in Figure 1, the wafer entire surface measurement system 1 was used to measure the thickness distribution over the entire surface of the wafer W, and the wafer outer periphery measurement system 2 was used to measure the thickness distribution only on the outer periphery of the wafer W within a range of 30 mm (outer periphery 30 mm) radially inward from the outermost periphery of the wafer W with a spatial resolution higher than that of the wafer entire surface measurement system 1. The spatial resolution (one measurement cell size) was set to 200 μm x 769 μm square for the wafer entire surface measurement system 1 and 30 μm x 115 μm square for the wafer outer periphery measurement system 2. At this time, an appropriate lens suited to the camera and the measurement target was used for each optical system. The cell size in the longitudinal direction can be set to the required spatial resolution by changing the scan speed, and the spatial resolution in the transverse direction can be changed by the number of pixels of the camera used.

[0068] (Comparative Example) Using a film thickness distribution measuring device equipped only with the entire wafer surface measurement system 1, the spatial resolution was set to 200 μm x 769 μm square (the same as the entire wafer surface measurement system 1 in the embodiment), and the film thickness distribution was measured over the entire surface of the wafer W.

[0069] The film thickness distribution of the film formed on the wafer was evaluated by using the film thickness distribution measurement results using the wafer full surface measurement system 1 for the film thickness distribution data of the central part of the wafer where the film thickness variation is relatively small, and the film thickness distribution data of the outer periphery of the wafer where the film thickness distribution tends to change rapidly and needs to be measured with higher accuracy, using the film thickness distribution measurement results using the wafer outer periphery measurement system 2. The evaluation results are shown in Figures 4 and 5. Figures 4(A) and (B) show the results of the comparative example, where Figure 4(A) is a film thickness distribution map of the entire wafer, and Figure 4(B) is a film thickness distribution map (upper figure) and cross-sectional film thickness distribution (lower figure) enlarged from the outer periphery (rectangular area surrounded by a black line) in Figure 4(A). Figure 5 shows the results of the example, where the film thickness distribution map (upper figure) and cross-sectional film thickness distribution (lower figure) of the same area as Figure 4(B). The film thickness distribution map of the entire wafer measured using the wafer full surface measurement system 1 in the example was the same as Figure 4(A).

[0070] As can be seen by comparing Figures 4(B) and 5, the film thickness distribution could be measured with high accuracy in the Example. In the Comparative Example, the influence of noise was observed, such as the spike-like film thickness distribution near the outermost circumference seen in the upper diagram of Figure 4(A) and the increase in film thickness value in the range of 3 mm on the periphery shown in the lower diagram, but the film thickness distribution could be measured with high accuracy up to the outermost circumference in the Example. Furthermore, since the Example measures with high spatial resolution only in the range of 30 mm on the periphery, it was possible to suppress an increase in measurement time (a decrease in throughput) while still performing highly accurate measurements.

[0071] The present specification includes the following aspects. [1]: A film thickness distribution measuring device for measuring the film thickness distribution of a film formed on a surface of a wafer, the film thickness distribution measuring device comprising an entire surface of the wafer measurement system that measures the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system that measures the film thickness distribution only in the outer periphery of the wafer surface excluding the center, the wafer outer periphery measurement system and the entire surface of the wafer measurement system being set to different spatial resolutions. [2]: The film thickness distribution measuring device according to [1] above, further comprising a parallel direction drive unit that moves the entire wafer surface measuring system and the wafer relatively in parallel in the surface direction of the wafer. [3]: The film thickness distribution measuring device of [1] or [2] above, further comprising a rotation direction drive unit that rotates the wafer outer periphery measuring system and the wafer relatively around the center of the wafer as an axis. [4]: The film thickness distribution measuring device according to [1], [2] or [3] above, further comprising a rotatable wafer placement section for placing the wafer thereon. [5]: The film thickness distribution measuring device according to [1], [2], [3] or [4], wherein the entire wafer measurement system and the outer periphery wafer measurement system are equipped with line optical systems. [6]: A film thickness distribution measurement method for measuring the film thickness distribution of a film formed on the surface of a wafer using a film thickness distribution measurement device that includes an entire surface of a wafer measurement system that measures the film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measurement system that measures the film thickness distribution only in the outer periphery of the wafer surface excluding the central portion, and that can set the wafer outer periphery measurement system and the entire surface of the wafer measurement system to different spatial resolutions, wherein the film thickness distribution is measured over the entire surface of the wafer using the entire surface of the wafer, and the film thickness distribution is measured only in the outer periphery of the wafer surface excluding the central portion using the wafer outer periphery measurement system with a spatial resolution higher than that of the entire surface of the wafer measurement system. [7]: The film thickness distribution measuring method according to [6] above, wherein the film thickness distribution is measured over the entire surface of the wafer while the entire surface of the wafer is moved parallel to the wafer in a direction parallel to the wafer surface. [8]: The film thickness distribution measurement method according to [6] or [7] above, wherein the wafer outer periphery measurement system and the wafer are rotated relatively around the center of the wafer as an axis, and the film thickness distribution is measured only on the outer periphery of the surface of the wafer, excluding the central portion. [9]: The film thickness distribution measuring method according to [6], [7] or [8] above, wherein the film thickness distribution is measured by the wafer full surface measurement system and the wafer outer periphery measurement system while rotating the wafer.

[10] : The film thickness distribution measuring method according to [6], [7], [8] or [9] above, wherein the entire wafer surface measuring system and the outer periphery wafer measuring system are equipped with line optical systems.

[0072] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0073] 1...wafer full surface measurement system, 2...wafer outer periphery measurement system, 3...parallel direction drive unit, 4, 4'... rotation direction drive unit, 5... wafer placement unit, 6... line optical system, 10...line light source, 13...detector, 100...film thickness distribution measuring device. L1, L2...line-shaped light, F...film (multilayer film), W...wafer.

Claims

1. A film thickness distribution measuring apparatus for measuring a film thickness distribution of a film formed on a surface of a wafer, comprising: the film thickness distribution measuring device comprises an entire wafer measuring system for measuring a film thickness distribution over the entire surface of the wafer, and a wafer outer periphery measuring system for measuring a film thickness distribution only in an outer periphery of the wafer surface excluding a central portion, 2. A film thickness distribution measuring apparatus, wherein the wafer outer periphery measuring system and the wafer entire surface measuring system can be set to different spatial resolutions.

2. 2. The film thickness distribution measuring device according to claim 1, further comprising a parallel direction drive unit for relatively moving the entire wafer measuring system and the wafer in parallel in the direction of the surface of the wafer.

3. 2. The film thickness distribution measuring device according to claim 1, further comprising a rotation direction drive unit for relatively rotating the wafer outer periphery measuring system and the wafer about an axis of rotation of the center of the wafer.

4. 2. The film thickness distribution measuring device according to claim 1, further comprising a rotatable wafer placement portion for placing the wafer thereon.

5. 5. The film thickness distribution measuring apparatus according to claim 1, wherein the entire wafer surface measuring system and the outer periphery wafer measuring system each include a line optical system.

6. A film thickness distribution measurement method for measuring a film thickness distribution of a film formed on a surface of a wafer using a film thickness distribution measurement device that includes an entire surface of a wafer measurement system that measures a film thickness distribution over the entire surface of the wafer, and a peripheral portion of the wafer measurement system that measures a film thickness distribution only in the peripheral portion of the surface of the wafer excluding a central portion, and that can set the peripheral portion of the wafer measurement system and the entire surface of the wafer measurement system to different spatial resolutions, comprising: Using the wafer full surface measurement system, a film thickness distribution is measured over the entire surface of the wafer, a wafer outer periphery measuring system for measuring a film thickness distribution only on the outer periphery of the surface of the wafer, excluding the central portion, with a spatial resolution higher than that of the entire surface of the wafer;

7. 7. The film thickness distribution measuring method according to claim 6, further comprising the steps of: measuring the film thickness distribution over the entire surface of the wafer while relatively translating the entire surface of the wafer measuring system and the wafer in a direction parallel to the surface of the wafer.

8. 7. The film thickness distribution measuring method according to claim 6, wherein the film thickness distribution of only the outer periphery of the surface of the wafer, excluding the central portion, is measured while the wafer outer periphery measuring system and the wafer are rotated relatively around the center of the wafer as an axis.

9. 7. The method of measuring a film thickness distribution according to claim 6, wherein the film thickness distribution is measured by the entire wafer measuring system and the outer peripheral wafer measuring system while the wafer is being rotated.

10. 10. The film thickness distribution measuring method according to claim 6, wherein the wafer entire surface measuring system and the wafer outer periphery measuring system are equipped with line optical systems.

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