Thin film stress measurement method, substrate for thin film stress measurement, device production method using same, and thin film stress measurement device

Abstract

Thin film stress (300) which is the internal stress of a thin film (101) is measured by performing the following: a step in which the thin film (101) is formed on a diaphragm array (108) that has a plurality of openings (103) with contour shapes of different sizes on the side of a support layer (102) joined with an active layer (106), said side being in contact with the active layer (106), and in which a plurality of diaphragms (107) formed by the active layer (106) and the openings (103) are arranged; a step in which deformation of the diaphragm array (108) is detected and the thin film stress (300) is calculated; and a step in which the calculated thin film stress (300) is output.

Description

Thin film stress measurement method, thin film stress measurement substrate, device manufacturing method using the same, and thin film stress measurement apparatus

[0001] The present disclosure relates to a thin film stress measurement method, a substrate for thin film stress measurement, a device manufacturing method using the same, and a thin film stress measurement apparatus.

[0002] Devices such as MEMS (Micro Electro Mechanical Systems) and IC chips, which use fine patterns to form operating parts such as ultrasonic sensors and pressure sensors, have significantly contributed to miniaturization, low power consumption, and low cost. During device manufacturing, thin film formation and etching are repeatedly performed on large-diameter substrates to form microstructures using fine patterns. When this thin film is formed on the surface of a substrate using a film-forming method such as CVD (Chemical Vapor Deposition) or sputtering, residual stress (hereinafter referred to as thin film stress) remains within the thin film, and the thin film stress varies depending on the conditions for forming the thin film. Furthermore, thin film stress can vary depending on the position on the substrate. Since the thin film stress of thin films formed using these film-forming methods affects the operation of devices, it is necessary to understand the thin film stress. Patent Document 1, for example, discloses a method for measuring thin film stress by measuring the warpage of a substrate on which a thin film is formed and calculating the thin film stress from the warpage of the substrate.

[0003] Japanese Patent Application Publication No. 07-235574

[0004] However, while conventional thin film stress measurement methods can measure the warpage of a substrate and determine the average thin film stress across the entire substrate, they have the problem of making it difficult to determine the stress distribution across the entire substrate, taking into account the thin film stress at a specific position and the thin film stress that varies depending on the position on the substrate.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a thin film stress measurement method that can determine the stress distribution over an entire substrate by grasping the thin film stress at a specific position or the thin film stress that varies depending on the position on the substrate. It also aims to provide a thin film stress measurement substrate used in this thin film stress measurement method, a device manufacturing method using the same, and a thin film stress measurement apparatus 300.

[0006] The thin film stress measurement method according to the present disclosure includes the steps of: forming a thin film on a diaphragm array in which a support layer bonded to an active layer has a plurality of apertures with different contour sizes on the side in contact with the active layer, and in which a plurality of diaphragms formed by the active layer and the apertures are arranged; detecting deformation of the diaphragms in the diaphragm array to calculate the thin film stress, which is the internal stress of the thin film; and outputting the calculated thin film stress.

[0007] In addition, the thin film stress measurement substrate according to the present disclosure includes a support layer having a plurality of apertures on its surface with different contour sizes, and an active layer provided on the support layer, and a plurality of arranged diaphragms that are provided to hold at least a portion of the internal space of the apertures.

[0008] In addition, a method for manufacturing a device according to the present disclosure includes the steps of: forming a thin film under at least one preset condition on a diaphragm array in which a support layer bonded to an active layer has a plurality of apertures with different contour sizes on the side in contact with the active layer, and a plurality of diaphragms formed by the active layer and the apertures are arranged; detecting deformation of the diaphragms in the diaphragm array and calculating thin film stress, which is the internal stress of the thin film; correlating the calculated thin film stress with positional information of the diaphragms to determine a stress distribution; determining whether the stress distribution is within a preset range and selecting a preset condition from the preset conditions that is within the range as a selected condition; and forming a thin film on a substrate based on the selected condition and processing the thin film.

[0009] In addition, a method for manufacturing a device according to the present disclosure includes the steps of: forming a thin film on a diaphragm array in which a support layer bonded to an active layer has a plurality of apertures with different contour sizes on the side in contact with the active layer, and a plurality of diaphragms formed by the active layer and the apertures are arranged; detecting deformation of the diaphragms in the diaphragm array to calculate thin film stress, which is the internal stress of the thin film; correlating the calculated thin film stress with positional information of the diaphragm array to determine the stress distribution; determining whether the stress distribution is within a predetermined set range and processing the thin film in a region included in the set range; and cutting out the region in which the thin film has been processed.

[0010] Furthermore, the thin film stress measurement device according to the present disclosure includes an observation table on which the thin film stress measurement substrate according to the present disclosure, on which a thin film is formed, is mounted; a detection unit that detects deformation of a diaphragm of the thin film stress measurement substrate; a stress distribution data creation unit that moves the observation table or the detection unit to associate position information of the diaphragm whose deformation has been detected with deformation information related to the deformation detected by the detection unit to generate stress distribution data; and a stress distribution data output unit that outputs the stress distribution data created by the stress distribution data creation unit.

[0011] According to the present disclosure, the thin film stress can be measured by forming a thin film on a diaphragm array in which diaphragms with different diameters or side sizes are arranged, and the distribution of the thin film stress at a specified position or the thin film stress of a substrate can be obtained.

[0012] 1 is a flowchart showing a process for measuring thin film stress according to embodiment 1. FIG. 2 is a perspective view of a diaphragm array according to embodiment 1. FIG. 3 is a top view of a diaphragm array according to embodiment 1. FIG. 4 is a cross-sectional view of a diaphragm array according to embodiment 1. FIG. 5 is a cross-sectional view of a diaphragm array according to embodiment 1. FIG. 6 is a perspective view of a diaphragm array according to embodiment 1. FIG. 7 is a relationship diagram showing the relationship between thin film stress at which buckling occurs and diaphragm diameter according to embodiment 1. FIG. 8 is a relationship diagram showing the relationship between the amount of deformation at the center of the diaphragm and thin film stress according to embodiment 1. FIG. 9 is an explanatory diagram explaining the state of deformation of the diaphragm according to embodiment 1. FIG. 10 is an explanatory diagram explaining the state of deformation of the diaphragm according to embodiment 1. FIG. 11 is a top view of a diaphragm array according to embodiment 1. FIG. 12 is a cross-sectional view of a diaphragm array according to embodiment 1. FIG. 13 is a relationship diagram showing the relationship between the amount of deformation at the center of the diaphragm and thin film stress according to embodiment 2. FIG. 14 is a top view of a diaphragm array according to embodiment 2. FIG. 15 is a cross-sectional view of a diaphragm array according to embodiment 2. FIG. 16 is a relationship diagram showing the relationship between the amount of deformation at the center of the diaphragm and thin film stress according to embodiment 2. FIG. 1 is a perspective view of a diaphragm array according to embodiment 3. FIG. 2 is a top view of a diaphragm array according to embodiment 3. FIG. 3 is a cross-sectional view of a diaphragm array according to embodiment 3. FIG. 4 is a top view of a diaphragm array according to embodiment 4. FIG. 5 is a perspective view of a thin film stress measurement substrate according to embodiment 5. FIG. 6 is a cross-sectional view of a thin film stress measurement substrate according to embodiment 5. FIG. 7 is a flowchart showing a process for manufacturing a device according to embodiment 6. FIG. 8 is a flowchart showing a process for manufacturing a device according to embodiment 6. FIG. 9 is a schematic diagram showing a thin film stress measurement apparatus according to embodiment 7. FIG. 10 is a block diagram showing a schematic configuration of an analysis unit of a thin film stress measurement apparatus according to embodiment 7. FIG. 11 is a schematic configuration diagram showing an example of a processing circuit that realizes each function of a thin film stress measurement apparatus.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that identical or corresponding parts in each drawing are designated by the same reference numerals. In the description of the embodiments, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0014] Embodiment 1. A thin film stress measurement method according to embodiment 1 will be described with reference to FIGS. 1 to 10. FIG. 1 is a flowchart showing steps for measuring thin film stress according to embodiment 1. As shown in FIGS. 2 to 5, the thin film stress measurement method includes a step (step S101) of forming a thin film 101 on a diaphragm array 108 in which a support layer 102 bonded to an active layer 106 has a plurality of apertures 103 with different contour sizes on the side in contact with the active layer 106, and a plurality of diaphragms 107 formed by the active layer 106 and the apertures 103 are arranged; a step (step S102) of detecting deformation of the diaphragms 107 in the diaphragm array 108 due to the formation of the thin film 101 and calculating the thin film stress, which is the internal stress of the thin film 101; and a step (step S103) of outputting the calculated thin film stress.

[0015] For example, the diaphragm 107 is formed on a substrate in which the support layer 102 and the active layer 106 are bonded together. Specifically, the diaphragm 107 is formed by etching the support layer 102 to form the apertures 103. For example, as shown in FIG. 2 , a diaphragm array 108 composed of a plurality of diaphragms 107 can be fabricated by forming an array of multiple apertures 103 with different diameters and circular contours in the flat support layer 102, and then providing an active layer 106 on the support layer 102 while ensuring internal space for the apertures 103. In FIG. 2 , the width of the flat support layer 102 is represented by the X axis, the depth by the Y axis, and the thickness by the Z axis. FIG. 3 is a top view of the diaphragm array 108 composed of a plurality of diaphragms 107 of FIG. 2 , showing the contours (dashed lines) of the apertures 103 on the surface of the support layer 102 as seen through the active layer 106. FIG. 3 shows an example in which a plurality of apertures 103 arranged in, for example, five rows and five columns are covered with an active layer 106 to form a plurality of diaphragms 107 with different diameters. The contours of the plurality of apertures 103 formed in the support layer 102 in contact with the active layer 106 are each circular. The apertures 103 have different sizes, i.e., different diameters. The apertures 103 penetrate the support layer 102 in the thickness direction. The through apertures 103 are formed, for example, by applying a resist to the surface opposite to the surface to which the active layer 106 is bonded, and then are deeply excavated by dry etching or the like. FIG. 4 is a cross-sectional view showing the A-A cross section in FIG. 3. The deeply excavated apertures 103 are covered with the active layer 106 while retaining at least a portion of their internal spaces. That is, the internal spaces of the apertures 103 are covered with the active layer 106 to form a plurality of diaphragms 107, resulting in a diaphragm array 108 in which a plurality of diaphragms 107 with different diameters are arranged. The thickness of the support layer 102 is, for example, about 400 to 600 μm, and the thickness of the active layer 106 is, for example, about 1 to 10 μm.

[0016] The diaphragm 107 is a part of the active layer 106 and is an elastic film that is deformable in the thickness direction of the active layer 106. One diaphragm 107 is formed for each opening 103, and a collection of a plurality of arranged diaphragms 107 forms a diaphragm array 108. The material of the support layer 102 and the active layer 106 is, for example, Si, SiC, Ge, Se, GaAs, GaN, InP, or the like.

[0017] Then, a thin film 101 is formed by, for example, CVD, sputtering, or the like on a diaphragm array 108 in which a plurality of diaphragms 107 of different sizes are arranged. Fig. 5 is a cross-sectional view showing a state in which the thin film 101 has been formed on the active layer 106 of Fig. 4. Fig. 6 is a perspective view of the diaphragm array 108 on which the thin film 101 has been formed.

[0018] The thin film 101 is, for example, a TEOS (tetraethoxy silane) film, a SiO2 film, or the like. Residual stress remains inside the thin film 101. Residual stress can be compressive stress or tensile stress, but the residual stress of the thin film 101 is usually compressive stress. When compressive stress remains inside the thin film 101, the compressive stress of the thin film 101 acts on the diaphragm 107 as thin film stress, and the diaphragm 107 deforms, for example, by protruding in the Z direction in FIG. 5.

[0019] Since the deformation of the diaphragms 107 in the diaphragm array 108 due to the compressive stress of the thin film 101 varies depending on the size of the diaphragms 107, i.e., the diameter or side size of the outline of the apertures 103, the thin film stress at a specified position can be measured by detecting the deformation of the diaphragms 107. For example, it is sufficient to check whether the diaphragms 107 are buckled. If there are multiple buckled diaphragms 107, the buckled diaphragm 107 with the smallest diameter is detected. For example, data relating the thin film stress at which buckling occurs and the size of the diaphragms 107, as shown in FIG. 7, is prepared, and the thin film stress corresponding to the smallest diameter of the buckled diaphragm 107 is determined. For example, the thin film stress at a specified position can be measured by outputting the thin film stress.

[0020] 8 shows data relating to the relationship between the thin film stress and the amount of deformation at the center of the diaphragm 107, which can be obtained by FEM (Finite Element Method) analysis. The amount of deformation at the center of the diaphragm 107 in FIG. 8 corresponds to, for example, the amount of deformation in the Z direction in FIG. 5, which is compressive thin film stress. For example, in FEM analysis, the shape of the diaphragm 107 resulting from the thin film stress can be obtained by inputting the thickness of the active layer 106, the thickness of the thin film 101, the diameter of the opening 103, etc.

[0021] In Figure 8, for diaphragms DF1 (solid line) and DF2 (dashed line) with different diameters, as the thin film stress increases, the amount of deformation at the center of diaphragm 107 increases and eventually reaches a maximum value Dmax. As the thin film stress increases further, the amount of deformation at the center of diaphragm 107 decreases and reaches a minimum value Dmin. At the maximum value Dmax, the diaphragm deforms by protruding upward along the Z axis as shown in Figure 9, and at the minimum value Dmin, the diaphragm deforms by protruding downward along the Z axis as shown in Figure 10.

[0022] When the diaphragm 107 deforms downward in a convex shape, buckling occurs in the diaphragm 107. The thin film stress at this time is referred to as the buckling stress. This phenomenon occurs regardless of the diameter of the diaphragm 107, and the buckling stress differs depending on the diameter. Therefore, if the smallest size of the buckling diaphragm 107 among the multiple diaphragms 107 in the diaphragm array 108 is detected, the thin film stress at a specific position can be calculated based on this.

[0023] Here, an example has been shown in which circular apertures 103 are formed and the contour shape of apertures 103 is circular, but the contour shape may also be a square as shown in FIG. 11 or a triangle as shown in FIG. 12. Other polygonal shapes such as a pentagon or hexagon are also possible. In other words, the contour shape of apertures 103 may be any of a circle, an ellipse, and a polygon. Diaphragms 107 and diaphragm arrays 108 including such diaphragms may be fabricated in any shape that is easy to process.

[0024] In this way, the thin film stress measurement method forms a thin film on a diaphragm array 108 in which a support layer 102 bonded to the active layer 106 has a plurality of apertures 103 with different contour sizes on the side in contact with the active layer 106, and a plurality of diaphragms 107 formed by the active layer 106 and the apertures 103 are arranged, detects the deformation of the diaphragm array 108 due to the formation of the thin film 101, calculates the thin film stress, which is the internal stress of the thin film 101, and outputs the calculated thin film stress, thereby measuring the thin film stress at a specified position.

[0025] If the deformed shape of the diaphragm 107 after the formation of the thin film 101 is not smooth but is irregular, the deformed shape of the diaphragm 107 may be corrected by pressurizing or depressurizing the atmosphere in contact with the diaphragm 107. For example, pressurizing or depressurizing to about 1 atmosphere may be performed. In this way, by pressurizing or depressurizing the atmosphere in contact with the diaphragm 107, the thin film stress can be measured more accurately.

[0026] Although an example in which the active layer 106 is provided on the support layer 102 has been shown, an oxide film 105 may be provided between the active layer 106 and the support layer 102 as shown in Fig. 13. When the material of the active layer 106 is, for example, single crystal silicon, the oxide film 105 functions as an etching stop when the support layer 102 is etched.

[0027] Furthermore, if the thickness of the formed active layer 106 differs from the set value obtained by FEM analysis, the thickness may be adjusted by polishing or the like. This can improve the accuracy of calculation of thin film stress by FEM analysis. By using single crystal silicon for the active layer 106 and providing an oxide film 105 between the support layer 102 and the active layer 106, it is easy to form the active layer 106 to have a target thickness. Therefore, thin film stress can be measured with high accuracy.

[0028] Although an example in which the openings 103 penetrate the support layer 102 has been shown, the openings 103 may have bottoms 104 within the support layer 102, as shown in FIG. 14 . The openings 103 having bottoms 104 may be formed in the support layer 102 by, for example, etching, and then sealed to form an internal space. The size of the openings 103 can be increased by processing the openings 103 from the top surface of the support layer 102 using dry etching or the like. Furthermore, the depth of the openings 103 is shallower than when etched from the back surface, allowing the openings 103 to be formed in a shorter time. The depth of each opening 103 may vary. The depth of the openings 103 is not particularly specified, but may be approximately 10 to 100 μm. Furthermore, even if an oxide film 105 is present on the support layer 102, the openings 103 can be formed by etching from the surface side of the support layer 102.

[0029] Embodiment 2. A thin film stress measurement method in embodiment 2 will be described. In embodiment 1, an example was described in which thin film stress was calculated based on the size of the smallest opening 103 of a buckling diaphragm 107 among a plurality of diaphragms 107 in a diaphragm array 108, but in embodiment 2, thin film stress is calculated based on the deformation amount of a non-buckling diaphragm 107 in the diaphragm array 108. The following description will focus on differences from embodiment 1, and descriptions of identical or corresponding parts will be omitted as appropriate.

[0030] The thin film stress measurement method according to the second embodiment includes steps similar to the steps for measuring the thin film stress according to the first embodiment shown in Fig. 1. In a step (step S102) of detecting deformation of the diaphragm 107 in the diaphragm array 108 due to the formation of the thin film 101 and calculating the thin film stress, which is the internal stress of the thin film 101, the amount of deformation at the center of the diaphragm 107 is measured using, for example, a surface profile measuring instrument.

[0031] The surface shape measuring device may be, for example, a white light interferometer, a laser microscope, an optical microscope, or a contact-type stylus surface roughness meter. The surface shape measuring device is used to measure the height position of the surface of the thin film 101 at the center of the diaphragm 107, and the amount of deformation in the Z direction at the center of the diaphragm 107 can be determined by subtracting the height of the flat portion of the undeformed surface of the thin film 101. When detecting deformation, the amount of deformation in the Z direction at a position shifted from the center of the diaphragm may also be used.

[0032] As in embodiment 1, this deformation amount varies depending on the size of the diaphragm 107 in the diaphragm array 108, i.e., the diameter or side size of the opening 103, so by detecting the deformation amount of the diaphragm 107, it is possible to measure the thin film stress at a specified position.

[0033] For example, as shown in FIG. 15 , similarly to the first embodiment, from the data on the relationship between the deformation amount at the center of the diaphragm 107 and the thin film stress obtained by FEM analysis, the thin film stress σ1 corresponding to the deformation amount D1 at the center of the diaphragm 107 measured by a surface shape measuring device is obtained in the stress range R1 where buckling does not occur.

[0034] In this way, the thin film stress at a specified position can be calculated by calculating the thin film stress based on the deformation amount of the non-buckling diaphragm 107 in the diaphragm array 108. Also, the thin film stress in the area where the diaphragm array 108 is formed can be found.

[0035] The deformation amount in the Z direction at the center of the diaphragm 107 can be measured using a piezoresistance in addition to being measured using a surface shape measuring device, and the thin film stress can be calculated based on this.

[0036] Fig. 16 is a top view of the diaphragm array 108 provided with the piezoresistance portion 110, and Fig. 17 is a cross-sectional view of the diaphragm array 108 taken along the line B-B in Fig. 16. As shown in Fig. 16 and Fig. 17, the piezoresistance portion 110 is provided in the active layer 106 of the diaphragm array 108, and the deformation amount of the diaphragm 107 can be determined based on the voltage of the piezoresistance portion 110 after the thin film 101 is formed on the diaphragm array 108.

[0037] In this thin film stress measurement method, in the process (step S102) of detecting the deformation of the diaphragm 107 in the diaphragm array 108 due to the formation of the thin film 101 and calculating the thin film stress, which is the internal stress of the thin film 101, the amount of deformation of the diaphragm 107 is determined based on the voltage of the piezoresistance section 110, and the thin film stress is calculated.

[0038] The piezoresistance elements 110 are formed by ion implantation of impurities such as boron or phosphorus into the surface of the active layer 106, which is made of, for example, single-crystal silicon. As shown in FIG. 16 , the piezoresistance elements 110 are formed, for example, at four locations on the edge of the diaphragm 107. The four piezoresistance elements 110 are wired to form a Wheatstone bridge circuit, outputting a voltage signal corresponding to the deformation of the diaphragm 107. The relationship between the output voltage of the piezoresistance elements 110 and the amount of deformation of the diaphragm 107 is linear, with a slope of dD / dV, as shown in FIG. 18 . Therefore, by using data relating the output voltage of the piezoresistance elements 110 and the amount of deformation at the center of the diaphragm 107, the amount of deformation at the center of the diaphragm 107 can be determined from the output voltage of the piezoresistance elements 110. Furthermore, by using the piezoresistance elements 110, it is possible to determine whether the deformation of the diaphragm 107 is convex upward or convex downward.

[0039] In this way, by forming the thin film 101 on the diaphragm array 108 in which the piezoresistance section 110 is provided in the active layer 106 located above the internal space created by the opening 103, and determining the amount of deformation of the diaphragm 107 based on the output voltage of the piezoresistance section 110, it is possible to detect the amount of deformation of the diaphragm 108 with higher accuracy. Then, the thin film stress can be measured from the detected amount of deformation.

[0040] Embodiment 3. A thin film stress measurement method in embodiment 3 will be described with reference to Figures 19 to 21. In embodiments 1 and 2, a method for detecting deformation of the diaphragm array 108 was described, but in embodiment 3, a metal thin film 109 is formed on the upper surface of the thin film 101 to detect deformation of the diaphragm array 108. The following description will focus on the differences from embodiments 1 and 2, and will omit descriptions of the same or corresponding parts as appropriate.

[0041] As shown in the perspective view of Fig. 19, the top view of Fig. 20, and the CC cross-sectional view of Fig. 21, a metal thin film 109 is formed on the top surface of the thin film 101 on the top surface of the diaphragm array 108. By providing the metal thin film 109 on the diaphragm array 108, the light reflectance is increased, making it easier to detect the amount of deformation of the diaphragm 107.

[0042] The metal thin film 109 may be any material that increases the reflectivity of light when measuring the deformation of the diaphragm 107. For example, a two-layer structure with Au as the surface layer and Ti or Cr as the middle layer is preferable, as this makes it easier to adhere Au, which has high light reflectivity.

[0043] The thickness of the metal thin film 109 is, for example, about 0.01 to 0.1 μm. The shape of the metal thin film 109 is not particularly limited and may be round or rectangular, but a cross shape makes it easy to align it with the center of the diaphragm 107 and to detect the amount of deformation. The metal thin film 109 only needs to be formed in an area that includes the center of the diaphragm 107, and may also be formed on the entire surface of the thin film 101.

[0044] If the thin film 101 has a property of transmitting light, a metal thin film 109 may be provided between the diaphragm array 108 and the thin film 101 .

[0045] In this way, by providing the metal thin film 109 directly on the diaphragm array 108 or via the thin film 101 and detecting the deformation of the diaphragms 107 in the diaphragm array 108 due to the formation of the thin film 101, the amount of deformation can be easily detected.

[0046] Embodiment 4 In embodiment 4, an example will be described in which a plurality of diaphragm arrays 108 are used to calculate the distribution of thin film stress across a large-diameter substrate, such as a wafer 111. This embodiment differs from embodiments 1 to 3 in that a plurality of diaphragm arrays 108 are distributed across the large-diameter substrate. The following description will focus on the differences from embodiments 1 to 3, and will omit descriptions of identical or corresponding parts as appropriate.

[0047] FIG. 22 shows an example of a wafer 111 on which at least one of the diaphragm arrays 108 described in the first to third embodiments is formed. The wafer 111 is, for example, an SOI wafer (Silicon-On-Insulator Wafer). For example, the diaphragm arrays 108 are formed on the wafer 111, radially dispersed at intervals of 45° from the center of the wafer 111. The angle can be changed as appropriate, and may be 15°, 30°, or the like. The diaphragm arrays may be randomly dispersed rather than radially. Furthermore, the positional information of the multiple diaphragm arrays 108 and the calculated thin film stress are associated, and the thin film stress is calculated based on the identified position when the thin film 101 is formed on the wafer 111. The positional information of the multiple diaphragm arrays or the diaphragms 107 in the multiple diaphragm arrays 108 may also be associated with the calculated thin film stress.

[0048] In this way, by forming the thin film 101 on the diaphragm array 108 in which a plurality of diaphragm arrays 108 are formed at predetermined positions, detecting the deformation of the diaphragms 107 in the diaphragm array 108 due to the formation of the thin film 101, and determining the thin film stress by correlating the calculated thin film stress with the positional information of the diaphragm array 108 or the diaphragm 107, it is possible to determine the thin film stress at specified positions over a wide range. It is also possible to determine the distribution of the thin film stress on the wafer 111.

[0049] Embodiment 5 In embodiment 5, a thin film stress measurement substrate 200 prepared for thin film stress measurement will be described. The thin film stress measurement substrate 200 can be fabricated in the same manner as the diaphragm array 108 described in embodiments 1 to 4. The following description will focus on the differences from embodiments 1 to 4, and descriptions of the same or corresponding parts will be omitted as appropriate.

[0050] 23 and 24 , the thin film stress measurement substrate 200 comprises a support layer 102 having a plurality of openings 103 with different contour sizes on its surface, and an active layer 106 provided on the support layer 102, and a diaphragm array 108 in which a plurality of diaphragms 107 are arranged, each diaphragm holding at least a portion of the internal space of the opening 103. The active layer 106 and the support layer 102 are bonded to form the thin film stress measurement substrate 200. When measuring thin film stress, a thin film 101 may be formed on the active layer 106 of the thin film stress measurement substrate 200.

[0051] In this way, the process of measuring thin film stress can be simplified by measuring thin film stress using a thin film stress measurement substrate 200 that includes a substrate 102 having a plurality of openings 103 with different contour sizes on its surface, and a diaphragm array 108 in which a plurality of diaphragms 107 are arranged, each diaphragm holding at least a portion of the internal space of the openings 103 by an active layer 106 provided on the support layer 102.

[0052] Sixth Embodiment A method for manufacturing a device according to a sixth embodiment will be described with reference to Fig. 25. Fig. 26 is a flowchart of the method for manufacturing a device according to the sixth embodiment. In the sixth embodiment, the thin film stress is calculated using the diaphragm array 108 according to any one of the first to fourth embodiments or the thin film stress measuring substrate 200 according to the fifth embodiment, and a device is manufactured.

[0053] In the device manufacturing method according to the sixth embodiment, a thin film 101 is formed on a diaphragm array 108 having a plurality of apertures 103 of different contour sizes on the side of a support layer 102 bonded to the active layer 106, the apertures 103 being bonded to the active layer 106, and an array of diaphragms 107 formed by the active layer 106 and the apertures 103 (step S201). The deformation of the diaphragm array 108 due to the formation of the thin film 101 is detected to calculate the thin film stress on the diaphragm array 108 (step S202). The calculated thin film stress is then correlated with the positional information of the diaphragm array 108 to determine the stress distribution (step S203). It is then determined whether the stress distribution falls within a predetermined range, and the preset conditions falling within the range are selected as the selected conditions (step S204). The thin film 101 is then formed on a substrate based on the selected conditions, and the thin film 101 is processed (step S205).

[0054] In this way, a thin film is formed under preset pre-set conditions on a diaphragm array in which multiple diaphragms of different sizes are arranged, the deformation of the diaphragms in the diaphragm array due to the formation of the thin film is detected to calculate the thin film stress, the calculated thin film stress is associated with the position information of the diaphragm to determine the stress distribution, it is determined whether the stress distribution is within a preset set range, the pre-set conditions that are within the set range are used as selection conditions, a thin film is formed on a substrate based on the selection conditions, and the thin film is processed, thereby determining the conditions under which a thin film with thin film stress suitable for the operating characteristics can be formed, and a device with excellent operating characteristics can be manufactured.

[0055] 26 may also be performed. That is, first, a thin film 101 is formed on a diaphragm array 108 having a plurality of openings 103 with different contour sizes on the side of a support layer 102 that is bonded to the active layer 106 and that contacts the active layer 106, and having an array of a plurality of diaphragms 107 formed by the active layer 106 and the openings 103 (step S301). Then, deformation of the diaphragm array 108 due to the formation of the thin film 101 is detected to calculate a thin film stress on the diaphragm array 108 (step S302). The calculated thin film stress is associated with position information of the diaphragm array 108 to determine a stress distribution (step S303). It is then determined whether the stress distribution is within a predetermined range, and the thin film 101 in a region that falls within the set range is processed (step S304). The region where the thin film 101 has been processed is then cut out (step S305).

[0056] In this way, by processing the area where the thin film 101 having a thin film stress suitable for the operating characteristics is formed and cutting it out, a device having excellent operating characteristics can be manufactured.

[0057] Seventh Embodiment A thin film stress measurement apparatus 300 according to a seventh embodiment will be described with reference to Figures 27 to 29. Figure 27 is a schematic diagram showing the thin film stress measurement apparatus 300. Figure 28 is a block diagram showing a schematic configuration of the analysis unit 309 of the thin film stress measurement apparatus 300 according to the seventh embodiment. In the seventh embodiment, a thin film stress measurement apparatus 300 will be described which measures thin film stress using the diaphragm array 108 according to any one of the first to fourth embodiments or the thin film stress measurement substrate 200 according to the fifth embodiment.

[0058] The thin film stress measurement device 300 includes an observation table 307 on which a thin film stress measurement substrate 200 having a thin film 101 formed thereon is mounted; a detection unit 304 that detects deformation of the diaphragm 107 in the diaphragm array 108 of the thin film stress measurement substrate 200; a stress distribution data creation unit 3093 that moves the observation table 307 or the detection unit 304 to associate position information of the diaphragm 107 whose deformation has been detected with deformation information related to the deformation detected by the detection unit 304 to generate stress distribution data; and a stress distribution data output unit 3094 that outputs the stress distribution data created by the stress distribution data creation unit 3093. 27 , the apparatus includes a support base 308, an L-shaped head 303 attached to the support base 308, a detection unit 304 attached inside the head 303, an observation table 307 for placing the thin film stress measurement substrate 200 on which the thin film 101 is formed, a stage 306 with the observation table 307 attached to its upper surface, the detection unit 304 for detecting deformation of the diaphragm 107, an analysis unit 309 for calculating the amount of deformation at the center of the diaphragm 107, a control unit 310 for controlling the operation of moving the above in the horizontal direction, a display unit 311 for displaying the calculation results of the thin film stress output from the analysis unit 309, an input unit 312 for receiving a signal for operating the stage 306, and an information processing device 315. The detection unit 304 and the analysis unit 309 are connected via an observation control cable 313, and the stage 306 and the control unit 310 are connected via a stage control cable 314. The thin film stress measuring device 300 is, for example, a white light interferometer, a laser microscope, an optical microscope, or the like.

[0059] The observation table 307 is a table on which the thin film stress measurement substrate 200 is placed. The thin film stress measurement substrate 200 is placed on the observation table 307 so that the thin film stress measurement substrate 200 can be replaced. In Fig. 28, a stage 306 to which the observation table 307 is attached is movable in the X-axis, Y-axis, and Z-axis directions. The stage 306 and the head 303 may be attached via a linear guide 305.

[0060] The detection unit 304 has at least one objective lens 301 and a lens holder 302 that fixes the objective lens 301. The detection unit 304 stores height information of the range being observed in a data storage unit 3092.

[0061] As shown in FIG. 28, the analysis unit 309 includes a diaphragm deformation state measurement unit 3091 , a data storage unit 3092 , a stress distribution data creation unit 3093 , and a stress distribution data output unit 3094 .

[0062] The information on deformation detected by the detection unit 304 may be the size of the smallest diaphragm 107 that has buckled in one diaphragm array 108. The information on deformation may also be the amount of deformation of the diaphragm 107. When the information on deformation is the size of the smallest diaphragm 107 that has buckled in one diaphragm array 108, the diaphragm deformation state measurement unit 3091 measures the size of the smallest diaphragm 107 that has buckled. When the information on deformation is the amount of deformation of the diaphragm 107, the diaphragm deformation state measurement unit 3091 calculates the difference between the height data of the surface of the thin film 101 outside the range of the diaphragm 107 on the observation substrate and the height data at the center of the diaphragm 107.

[0063] The data storage unit 3092, which stores data indicating the relationship between diaphragm deformation and thin film stress, stores relationship data between the deformation state and thin film stress. When the information regarding the deformation detected by the detection unit 304 is the size of the smallest diaphragm 107 among the buckled diaphragms 107 in one diaphragm array 108, the relationship data between the thin film stress at which buckling occurs and the size of the diaphragm 107, as shown in Figure 7, is stored in the data storage unit 3092. When the information regarding the deformation detected by the detection unit 304 is the deformation amount of the diaphragm 107, the data storage unit 3092 stores relationship data between the deformation amount at the center of the diaphragm 107 and thin film stress, as shown in Figure 15.

[0064] The stress distribution data creation unit 3093 combines the thin film stress based on the size of the buckled diaphragm 107 in one diaphragm array 108, or the thin film stress based on the deformation amount of the diaphragm 107, with the positional information of each diaphragm 107 or each diaphragm array 108 to create stress distribution data.

[0065] The stress distribution data output unit 3094 outputs the stress distribution data created by the stress distribution data creation unit 3093 to the display unit 311 .

[0066] In this way, by providing an observation table 307 on which the thin film stress measurement substrate 200 having the thin film 101 formed thereon is mounted, a detection unit 304 that detects deformation of the diaphragm array 108 of the thin film stress measurement substrate 200, a stress distribution data creation unit 3093 that moves the observation table 307 or the detection unit 304 to associate position information of the diaphragm array 108 with deformation information related to the deformation detected by the detection unit 304 to create stress distribution data, and a stress distribution data output unit 3094 that outputs the stress distribution data, thin film stress can be easily measured.

[0067] Here, each function of the information processing device 315 is realized by a processing circuit. Fig. 29 is a schematic configuration diagram showing an example of a processing circuit that realizes each function of the information processing device 315. The information processing device 315 has a processor 316, a storage device 317, a communication I / F (interface) 318, a CAN (Controller Area Network) I / F (interface) 319, etc. For example, a CPU (Central Processing Unit) is used as the processor 316. The storage device 317 transmits and receives data to and from the processor 316 and stores the data.

[0068] The processor 316 and the storage device 317 may be shared by one processor or may be provided in multiple units. The processor 316 may include, for example, an application specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a logic circuit using an FPGA (field programmable gate array), or various signal processing circuits. Multiple processors 316, either of the same type or different types, may be provided, so that each process is shared and executed by multiple arithmetic processing devices.

[0069] The multiple storage devices 317 include, for example, a RAM (Random Access Memory) configured to allow data to be read from and written to the processor 316, a ROM (Read Only Memory) configured to allow data to be read from the processor 316, a hard disk (HDD), etc.

[0070] Each function of the information processing device 315 is realized by the processor 316 executing software or programs stored in the storage device 317 and working in cooperation with hardware. Setting data to be set in the information processing device 315 may be stored in the storage device 317 as part of the software or program, or may be input by the user. A non-transitory recording medium 321 on which the information processing program 320 is recorded may be distributed and installed in the storage device 317 of the information processing device 315.

[0071] Although various exemplary embodiments are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, and even cases where at least one component is extracted and combined with components of another embodiment.

[0072] 200 Thin film stress measurement substrate, 101 Thin film, 102 Support layer, 103 Opening, 104 Bottom, 105 Oxide film, 106 Active layer, 107 Diaphragm, 108 Diaphragm array, 109 Metal thin film, 110 Piezoresistive section, 111 Wafer, 300 Thin film stress measurement apparatus, 301 Objective lens, 302 Lens holder, 303 Head, 304 Detection section, 305 Linear guide, 306 Stage, 307 Observation table, 308 Support table, 309 Analysis section, 310 Control section, 311 Display section, 312 Input section, 313 Observation control cable, 314 Stage control cable, 3091 Diaphragm deformation state measurement section, 3092 Data storage section, 3093 Stress distribution data creation section, 3094 Stress distribution data output section

Claims

1. A thin film stress measurement method comprising the steps of: forming a thin film on a diaphragm array in which a plurality of diaphragms formed by the active layer and the openings are arranged, the support layer having a plurality of openings of different sizes in the contour shape on the side in contact with the active layer; detecting the deformation of the diaphragms in the diaphragm array and calculating the thin film stress, which is the internal stress of the thin film; and outputting the calculated thin film stress.

2. A thin film stress measuring method according to claim 1, wherein the thin film stress is calculated based on the smallest size of the buckling diaphragm among the plurality of diaphragms in the diaphragm array.

3. A method for measuring thin film stress according to claim 1, wherein the calculation of the thin film stress is performed based on the amount of deformation of the diaphragms in the diaphragm array that do not buckle.

4. A method for measuring thin film stress according to claim 3, wherein a piezoresistance section is provided in the active layer located above the aperture, and the amount of deformation of the diaphragm is determined based on the voltage of the piezoresistance section after the thin film is formed on the diaphragm array.

5. A thin film stress measuring method according to claim 1, wherein a metal thin film is provided directly on the diaphragm array or via the thin film, and deformation of the diaphragms in the diaphragm array due to the formation of the thin film is detected.

6. A thin film stress measurement method according to any one of claims 1 to 5, wherein the contour shape of the opening on the surface of the support layer is either a circle, an ellipse or a polygon.

7. A thin film stress measurement method according to any one of claims 1 to 6, further comprising a step of pressurizing or depressurizing the atmosphere in contact with the thin film formed on the diaphragm array.

8. A thin film stress measurement method according to any one of claims 1 to 7, wherein the active layer is single crystal silicon, and an oxide film is provided between the active layer and the support layer.

9. A thin film stress measurement method according to any one of claims 1 to 8, wherein the openings formed in the support layer are open on the side facing the active layer, and the active layer forms the diaphragm.

10. A thin film stress measurement method according to any one of claims 1 to 8, wherein the opening provided in the support layer has a bottom within the support layer, and the opening is sealed by the active layer.

11. A thin film stress measurement method according to any one of claims 1 to 10, in which a plurality of diaphragm arrays are formed at predetermined positions on a wafer, a thin film is formed on the diaphragm array, and the thin film stress calculated by detecting deformation of the diaphragms in the diaphragm array due to the formation of the thin film is associated with positional information of the diaphragm array or the diaphragm in the diaphragm array to determine the stress distribution.

12. A substrate for measuring thin film stress, comprising: a support layer having a plurality of apertures on its surface, each aperture having a different contour size; and an active layer provided on the support layer, and a plurality of arranged diaphragms that hold at least a portion of the internal space of the apertures.

13. A method for manufacturing a device, comprising the steps of: forming a thin film under at least one preset condition on a diaphragm array in which a support layer to be bonded to an active layer has a plurality of openings with different contour sizes on the side in contact with the active layer, the diaphragm being an array of diaphragms formed by the active layer and the openings; detecting deformation of the diaphragms in the diaphragm array and calculating thin film stress, which is the internal stress of the thin film; determining a stress distribution by correlating the calculated thin film stress with position information of the diaphragm; determining whether the stress distribution is within a preset range and selecting, as a selected condition, the preset condition included in the range from among the preset conditions; and forming a thin film on a substrate based on the selected condition and processing the thin film.

14. A method for manufacturing a device, comprising the steps of: forming a thin film on a diaphragm array in which a support layer to be bonded to an active layer has a plurality of openings with different contour sizes on the side in contact with the active layer, and in which a plurality of diaphragms formed by the active layer and the openings are arranged; detecting deformation of the diaphragms in the diaphragm array and calculating thin film stress, which is the internal stress of the thin film; correlating the calculated thin film stress with positional information of the diaphragm array to determine a stress distribution; determining whether the stress distribution is within a predetermined set range and processing the thin film in a region included in the set range; and cutting out the region in which the thin film has been processed.

15. A thin film stress measuring device comprising: an observation stand on which a thin film stress measuring substrate according to claim 12, on which a thin film is formed, is mounted; a detection unit for detecting the deformation of the diaphragm of the thin film stress measuring substrate; a stress distribution data creation unit for moving the observation stand or the detection unit and associating the position information of the diaphragm where deformation has been detected with the deformation information related to the deformation detected by the detection unit to obtain stress distribution data; and a stress distribution data output unit for outputting the stress distribution data created by the stress distribution data creation unit.

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