JP2009294001A - Strain measuring method and strain measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for measuring the strain of a board simply. <P>SOLUTION: Prior to performing processing on a board having a plurality of elements, the strain measuring method includes: a pattern forming step of forming a periodic pattern having a constant period; a reference board preparing step of preparing a reference board by forming a periodic pattern having a constant period on another board; an observing step of overlaying the board after being subjected to the processing on the reference board and observing stripes caused by the overlapping of the periodic patterns; and a measuring step of measuring the strain of the board from the observation result in the observing step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a strain measurement method and a strain measurement device. More specifically, a strain measurement method for simply measuring the strain generated in the substrate when a certain process is performed on the substrate such as a wafer, and a strain measurement device used when the strain measurement method is performed. About.

  There is a stacked semiconductor device in which substrates each having an element and a circuit formed thereon are stacked (see Patent Document 1). A stacked semiconductor device having a three-dimensional circuit structure has an effective high mounting density without increasing the mounting area. In addition, since the stacked structure has a short wiring length between the stacked substrates, it contributes to an improvement in operation speed and low power consumption.

  In the case of bonding the stacked substrates, a pair of substrates held in parallel with each other are aligned and stacked accurately with line width accuracy of the semiconductor circuit, and then heated and pressed to join the entire substrate. For this reason, the joining apparatus which combined the positioning apparatus (refer patent document 2) which aligns a pair of board | substrate correctly, and the heating / pressurizing apparatus (patent document 3) which hold | maintains joining permanently by heating and pressurization is used. It is done.

JP 11-261000 A JP 2005-251972 A JP 2007-114107 A

  When a pair of substrates are bonded in a heating and pressing apparatus, stress is applied to the substrate in a high temperature environment, and thus the substrate may be distorted. Such distortion can be measured by using a precise measuring instrument such as an interferometer. However, precise measuring instruments are expensive and difficult to introduce. Moreover, since skill is required for the operation of the measuring device, the range of use is limited. For this reason, there is a need for a technique that can be easily used even at a production site and that effectively measures strain generated in a processed substrate.

  In order to solve the above problems, as a first embodiment of the present invention, a pattern forming stage for forming a periodic pattern having a certain period before processing is performed on a substrate on which a plurality of elements are formed, and others A reference substrate preparation stage for preparing a reference substrate on which a periodic pattern having a certain period is formed, and observing a striped pattern generated by overlapping the periodic patterns by superimposing the processed substrate on the reference substrate There is provided a strain measurement method comprising a stage and a measurement stage for measuring the strain of the substrate from the observation result in the observation stage.

  Further, as a second embodiment of the present invention, a substrate holding portion that holds a substrate on which a plurality of elements are formed, in which a periodic pattern having a constant period is formed, and a reference that has a periodic pattern formed at a constant period A reference substrate holding unit that holds the substrate over the substrate, and an imaging device that captures the stripes generated by the overlapping of the periodic patterns in the overlapping substrate and the reference substrate, in a striped pattern shape captured by the imaging device A strain measuring device for measuring the strain of a substrate based on the above is provided.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solution of the invention.

  FIG. 1 is a cross-sectional view schematically showing the structure of the strain measuring device 100. The strain measurement apparatus 100 includes a base 110, a substrate holding unit 120, a reference substrate holding unit 140, an illumination unit 160, an imaging device 170, an image processing device 180, and an image display device 190.

  The base 110 includes a cover 112 that covers the substrate holding unit 120, the reference substrate holding unit 140, the illumination unit 160, and the imaging device 170. Thereby, the strain measurement with respect to the board | substrate 130 is performed in the environment interrupted | blocked from the outside.

  The substrate holding unit 120 includes a tilt stage 122, an elevating stage 124, and a rotating stage 126 that are sequentially stacked on the flat upper surface of the base 110. Further, the rotary stage 126 has an abutting member 121 and an abutting member 123 on the upper surface.

  The contact member 121 supports the sharp tip by contacting the lower surface of the substrate 130. The abutting member 123 positions the substrate 130 by abutting against the side surface of the substrate 130. Thereby, the rotation stage 126 positions and mounts the substrate 130 at a predetermined position.

  On the other hand, the tilt stage 122 tilts the mounted lifting stage 124 at an arbitrary tilt angle with respect to the upper surface of the base 110. The elevating stage 124 moves the mounted rotary stage 126 up and down. The rotation stage 126 rotates the mounted substrate 130 in a single plane as will be described later.

  By the cooperation of the tilt stage 122, the elevating stage 124, and the rotary stage 126, the substrate holding unit 120 makes the substrate 130 parallel to a reference substrate 150 described later. Further, it is held close to the reference substrate 150. The substrate 130 to be held can be, for example, a silicon wafer having a diameter of 200 mm or 300 mm. Further, it may be a laminated substrate in which a pair of silicon wafers each formed with elements, circuits, etc. are positioned and laminated with each other.

  The reference substrate holding unit 140 includes a support column 142 that extends upward from the substrate holding unit 120. The column 142 has an abutting member 141 and an abutting member 143 on the upper surface. The contact member 141 supports the sharp tip by contacting the lower surface of the reference substrate 150. The abutting member 143 positions the reference substrate 150 by abutting against the side surface of the reference substrate 150. Thereby, the reference board 150 is horizontally positioned at a predetermined position.

  The illumination unit 160 irradiates illumination light obliquely from above toward the reference substrate 150 supported by the reference substrate holding unit 140. Part of the illumination light emitted from the illumination unit 160 passes through the reference substrate 150 and is also applied to the substrate 130 supported by the substrate holding unit 120.

  The imaging device 170 images the reference substrate 150 and the substrate 130 illuminated by the illumination unit 160 from obliquely above. In the drawing, the illumination unit 160 and the imaging device 170 are drawn at symmetrical positions with respect to the reference substrate 150. However, since the reflectance of the substrate 130 such as a silicon wafer is high, the initial reflection of illumination light is performed. Is preferably arranged so as not to enter the imaging device 170.

  The image processing device 180 processes the signal of the image captured by the imaging device 170 and causes the image display device 190 to display the processed signal. Thereby, as will be described later, the distortion of the substrate 130 can be observed. Further, as will be described later, the distortion generated in the substrate 130 can be quantified by processing the observed image signal.

  FIG. 2 is a diagram illustrating an example of the reference substrate 150 prepared prior to strain measurement. The reference substrate 150 includes, for example, a transparent glass substrate 154 for a reticle and a periodic pattern 152 formed on the glass substrate 154. The periodic pattern 152 is formed as a number of parallel lines parallel to one side of the glass substrate 154.

  However, the periodic pattern 152 is not limited to a parallel line pattern. That is, any pattern can be used as long as it has a constant period, such as concentric circles. However, by forming a pattern having a certain angle with respect to the shape of the glass substrate, it is possible to predict the shape of the stripes generated in the observation stage and to perform high-speed image processing.

  FIG. 3 is a flowchart showing a procedure for carrying out the strain measurement method. More specifically, it is a flowchart showing an operation procedure when measuring strain of a silicon wafer or the like using the strain measurement apparatus 100 shown in FIG. 1 and the reference substrate 150 shown in FIG. Hereinafter, each work procedure will be described with reference to FIG.

  First, as shown in FIG. 4, a pattern formation stage for forming a periodic pattern 132 is executed on a substrate 130 such as a wafer 134 to be subjected to strain measurement (step S <b> 101). The wafer 134 is a silicon wafer, for example, and may be a wafer before a plurality of elements are formed by various processes, or may have already been formed with a plurality of elements. Further, a silicon wafer having a plurality of elements may be aligned and bonded. The periodic pattern 132 is formed as a number of parallel lines parallel to the orientation flat 136 of the wafer 134.

  However, the periodic pattern 132 is not limited to the parallel line pattern. That is, any pattern can be used as long as the pattern has a constant period, such as a lattice, halftone dot, or concentric circle. However, by forming a pattern formed at a fixed angle with reference to the orientation flat 136 and the like, it is possible to predict moire generated in the observation stage and set appropriate observation conditions. In addition, the accuracy of strain measurement can be improved.

  When the illumination light emitted from the illumination unit 160 is visible light such as e-line (wavelength 546.1 nm) used for Newton fringe observation, for example, the reflectance of the silicon wafer that is the substrate 130 is high. By using a material that absorbs light, the periodic pattern 132 that is easy to observe can be formed. Specifically, a low reflection chromium film, a TiN film, a W film, or the like deposited on the surface of the substrate 130 can be formed by patterning by photolithography, but the material and the formation method are not limited to these. .

  Referring again to FIG. 3, the substrate 130 on which the periodic pattern 132 is formed is loaded into the strain measuring apparatus 100 (step S102). That is, the substrate 130 is mounted on the substrate holding unit 120 in the strain measuring apparatus 100.

  FIG. 5 is a diagram showing a positioning method of the substrate 130 in the strain measuring apparatus 100, and shows a state where the rotary stage 126 on which the substrate 130 is mounted is looked down from above. On the rotary stage 126, the substrate 130 is supported by the three contact members 121. Thereby, the substrate 130 is positioned on a specific plane defined by the tip of the contact member 121.

  In addition, the substrate 130 abuts the orientation flat 136 against two of the three abutting members 123 and further abuts the arc-shaped side surface against the other abutting member 123. It is placed on the member 121. Thereby, the board | substrate 130 is positioned by the specific direction in the specific position in the said specific plane.

  As already described, the periodic pattern 132 of the substrate 130 is formed in parallel to the orientation flat 136. Therefore, the periodic pattern 132 of the substrate 130 mounted on the substrate holding unit 120 is also positioned in a specific direction with respect to the strain measuring apparatus 100.

  Referring to FIG. 3 again, next, the reference substrate 150 is loaded into the strain measuring apparatus 100 (step S103). That is, the reference substrate 150 is mounted on the reference substrate holding unit 140 in the strain measurement apparatus 100.

  FIG. 6 is a diagram illustrating a positioning method of the reference substrate 150 in the strain measurement apparatus 100, and illustrates a state in which the reference substrate holding unit 140 on which the reference substrate 150 is mounted is looked down from above. On the upper end surface of the support column 142, the reference substrate 150 is supported by the three contact members 141. Thereby, the reference substrate 150 is positioned on a specific plane defined by the tip of the contact member 141.

  Further, the reference substrate 150 is placed on the contact member 141 in a state where one side is abutted against two of the three abutting members 143 and the other one abutting side is abutted against the other abutting member 123. It is done. Thereby, the reference board 150 is positioned at a specific position in the specific plane.

  As already described, the periodic pattern 152 of the reference substrate 150 is formed in parallel to one side of the glass substrate. Therefore, when mounted on the reference substrate holding unit 140 in an appropriate orientation, the periodic pattern 152 of the reference substrate 150 forms a certain angle with the periodic pattern 132 of the substrate 130 mounted on the substrate holding unit 120. Furthermore, by rotating the rotary stage 126, the periodic patterns 132 and 152 of the substrate 130 and the reference substrate 150 can intersect at an arbitrary angle.

  When the substrate 130 and the reference substrate 150 are inserted, the cover 112 of the strain measuring device 100 is closed, and hereinafter, the strain of the substrate 130 is measured by external control. Referring to FIG. 3 again, first, by operating the tilt stage 122, the substrate 130 mounted on the substrate holding unit 120 is leveled (step S104). Next, the rotary stage 126 is operated to rotate the substrate 130, thereby intersecting the periodic patterns 132 and 152 (step S105).

  FIG. 7 is a diagram illustrating an image 192 displayed on the image display device 190 in step S108. More specifically, an image 192 obtained when the imaging device 170 images the substrate 130 and the reference substrate 150 that are loaded and superimposed on the strain measuring device 100 is depicted.

  In the strain measurement apparatus 100, when the substrate 130 having the periodic pattern 132 is mounted on the substrate holding unit 120 and the rotation stage 126 is rotated to slightly intersect the periodic patterns 132 and 152 of the substrate 130 and the reference substrate 150, they overlap. In the image 192 obtained by capturing the periodic patterns 132 and 152, a plurality of moire fringes 191 appear. Moire fringes 191 appear as parallel stripes that are not included in any of the periodic patterns 132 and 152. Thereby, an observation stage for observing the strain of the substrate 130 is executed.

  Note that the imaging device 170 in the strain measurement device 100 images the reference substrate 150 and the substrate 130 from an oblique direction, as shown in FIG. Therefore, the image included in the light incident on the imaging device 170 has a large trapezoidal distortion. Therefore, it is preferable that the image processing apparatus 180 displays the image display apparatus 190 after correcting the trapezoidal distortion of the image obtained from the imaging apparatus 170. Further, it is preferable that the processing of the fringe analysis program for analyzing the distribution of the distance between the reference substrate 150 and the substrate 130 based on the shape of the moire fringes 191 is also executed on the image after correcting the trapezoidal distortion.

  In addition, the periodic pattern 132 itself may not be completely linear. However, any error that can be expressed by a lower order of the fourth order or less can be compensated relatively easily.

  As described above, the strain measurement method includes an imaging stage in which the imaging device 170 having an imaging plane inclined with respect to the surface of the substrate 130 is imaged, and an image obtained by the imaging device 170 is displayed on the surface of the substrate 130. An observation stage including a correction stage for correcting an image appearing on an image plane parallel to the image plane. As a result, monitoring by the image display device 190 is facilitated, and processing in the resolution fringe analysis program is reduced, so that accurate and high-speed processing can be performed.

  Subsequently, the moire fringes 191 are imaged by the imaging device 170, and the distortion of the substrate 130 is measured (step S106). That is, the image processing apparatus 180 executes a fringe analysis program for analyzing the distribution of the distance between the reference substrate 150 and the substrate 130 based on the shape of the moire fringes 191.

  Although there may be some distortion in the substrate 130 before processing, which will be described later, in this embodiment, it is assumed that there is no distortion in the substrate 130 at this stage. Therefore, the moire fringes 191 appearing in the image 192 are parallel to each other. Based on this, the image processing apparatus 180 measures the shape of the substrate 130 before the heating and pressurizing process described later is performed.

  Further, in the above-described embodiment, the moire fringes 191 are observed through the reference substrate 150 that is loaded with the substrate 130 first and then loaded thereon. However, for example, when the substrate 130 is a silicon wafer, the moire fringes 191 can be observed by transmitting the substrate 130 with infrared rays.

  In this way, the substrate holding unit 120 that holds the substrate 130 on which the periodic pattern 132 having a constant cycle is formed, and the reference substrate 150 that holds the reference substrate 150 that has the periodic pattern 152 formed at a constant cycle on the substrate 130. The holding unit 140 and the imaging device 170 that captures the moire fringes 191 generated by the overlapping of the periodic patterns 132 and 152 in the overlapping substrate 130 and the reference substrate 150, and the shape of the moire fringes 191 captured by the imaging device 170 are provided. Based on this, the strain measuring apparatus 100 that measures the strain of the substrate 130 is formed. Thereby, the fine distortion of the substrate 130 can be measured with simple equipment and a simple method.

  Referring to FIG. 3 again, next, the intersection angle of the periodic patterns 132 and 152 is changed (step S107), and the distortion of the substrate 130 is measured again (step S108). That is, by operating the rotary stage 126, the crossing angle of the periodic patterns 132 and 152 is changed, and a moire fringe 191 different from the moire fringe 191 shown in FIG. 7 is generated. Furthermore, by executing a fringe analysis program based on the different moire fringes 191, the distortion of the substrate 130 is measured again.

  FIG. 8 is a diagram illustrating another image 192 displayed on the image display device 190. This image 192 is generated when the periodic pattern 132 of the substrate 130 shown in FIG. 7 is intersected with the periodic pattern 152 at a larger intersection angle, and the number of moire fringes 191 is increased.

  That is, when measuring a large distortion of the substrate 130, it is preferable to reduce the crossing angle of the periodic patterns 132 and 152 and widen the interval between the moire fringes 191. On the other hand, when measuring a small distortion of the substrate 130, it is preferable to increase the crossing angle of the periodic patterns 132 and 152 to narrow the interval between the moire fringes 191.

  As described above, the observation step may include a re-observation step of observing other moire fringes 191 generated by changing the crossing angle at which the periodic pattern 132 of the substrate 130 and the periodic pattern 152 of the reference substrate 150 intersect. As a result, distortions having different sizes can be reflected in the moire fringes 191 to accurately measure the distortions.

  Referring to FIG. 3 again, next, the substrate 130 is subjected to heat and pressure treatment (step S109). That is, as an example of a process performed on the substrate 130, in the present embodiment, a heating and pressing process on the substrate 130 is performed.

  FIG. 9 is a diagram schematically showing the structure of the heating and pressing apparatus 200. The heating and pressing apparatus 200 includes a pair of presses 210, a wafer holder 220, and a heating unit 230.

  The pair of wafer holders 220 holds the wafer 131 on each surface. The pair of presses 210 press the wafers 131 facing each other while being held by the wafer holder 220. Further, the pair of heating units 230 are incorporated in each of the presses 210 and heat the wafer 131 through the press 210 and the wafer holder 220.

  By using such a heating and pressing apparatus 200, a pair of wafers 131 are bonded by applying pressure while heating according to a predetermined temperature profile. The bonded wafer 131 can be handled as a single substrate 130. In addition, by forming the periodic pattern 132 in advance on each back surface of the wafer 131, the pair of bonded wafers 131 can also be handled as the substrate 130 having the periodic pattern 132.

  As described above, the process for the substrate 130 may include, for example, a bonding process performed by the heating and pressing apparatus 200 including the press 210 that presses the wafer 131 in a state of being overlapped with another wafer 131. However, the process for generating distortion in the substrate 130 is not limited to the heat and pressure process.

  Further, in the case where the heating and pressurizing process is performed on the substrate 130, it is preferable to perform the bonding process with a constant angle formed by the orientation flat 136 of the substrate 130 with respect to the heating and pressing apparatus 200. Thereby, the pressure or heat distribution acting on the substrate 130 in the heating and pressing apparatus 200 can be evaluated.

  Referring again to FIG. 3, as described above, the strain is again measured for the substrate 130 that has been subjected to the heating and pressurizing process (step S110). Thereby, the distortion of the substrate 130 caused by the process can be extracted by comparing the measured distortion of the substrate 130 with the distortion measured before the process.

  FIG. 10 is a diagram illustrating an image 192 displayed on the image display device 190 when the procedure from step S102 to step S105 is executed again after the heating and pressing process. In this image 192, a deformed pattern 193 is generated at one of the three moire fringes 191.

  That is, the period of the moire fringes 191 generated by the intersecting periodic patterns 132 and 152 is constant, but the mutual positions of the periodic patterns 132 and 152 are shifted in the direction intersecting the periodic patterns 132 and 152 due to the distortion of the substrate 130. In such a case, the interval of the moire fringes 191 changes. The deformed pattern 193 is formed by the change in the interval between the moire fringes 191. In other words, the distortion of the substrate 130 can be measured based on the change in the interval of the moire fringes 191 included in the deformation pattern 193.

  Note that when the shift of the periodic pattern 132 due to the distortion of the substrate 130 is completely parallel to the line pattern included in the periodic pattern 132, the deformed pattern 193 does not occur. However, since the distortion generated in the substrate 130 is continuous, the distortion does not occur only in a specific direction. Therefore, the planar distortion of the substrate 130 can be effectively detected by the periodic pattern 132 formed by parallel lines.

  Thus, it can be seen that the substrate 130 is distorted in the region where the deformation pattern 193 is generated. Further, by processing such an image 192 with a fringe analysis program executed by the image processing apparatus 180, the distortion generated in the substrate 130 can be measured numerically.

  In this way, a pattern forming stage for forming a periodic pattern having a fixed period before the processing is performed on the substrate 130 having a plurality of elements, and a periodic pattern having a fixed period on another substrate are performed. Forming a reference substrate by forming a reference substrate, observing stripes generated by overlapping periodic patterns by superimposing the processed substrate on the reference substrate, and distorting the substrate from the observation results in the observation step A strain measurement method comprising a measurement stage for measuring

  11 displays the moire fringes 191 generated when the substrate 130 is rotated by the operation of the rotary stage 126 (step S107) and the periodic patterns 132 and 152 intersect at the intersection angle shown in FIG. It is a figure which shows a state made to do.

  In the image 192 shown in FIG. 11, as in the case shown in FIG. 8, the interval between the moire fringes 191 is narrower, and more moire fringes 191 are generated than in the case of FIG. Further, a plurality of deformation patterns 193 different from the image 192 shown in FIG. 10 are generated in accordance with the distortion generated in the substrate 130 by the heat and pressure treatment. By processing the image 192 including such a deformed pattern 193 by the fringe analysis program, the distortion generated on the substrate 130 in the region where the deformed pattern 193 occurs can be measured at different scales.

  As described above, the observation step includes a pre-observation step in which the substrate 130 is overlapped with the reference substrate 150 and the moire fringes 191 generated by the overlap of the periodic patterns 132 and 152 are observed before the processing on the substrate 130 is performed. The measurement stage may include a detection stage in which the moiré fringes 191 observed in the previous observation stage are compared with the moiré fringes 191 observed in the observation stage to detect distortion generated in the substrate 130 by the processing. Thereby, the influence which the process has on the substrate 130 can be measured by a simple facility and a simple method.

  In addition, when the angle between the periodic patterns 132 and 152 is 2θ, the period of the moire fringes 191 appearing by the intersecting periodic patterns 132 and 152 is expanded to 1 / 2θ times the pitch of the periodic patterns 132 and 152. . Further, the change in the distance between the substrate 130 on which the periodic patterns 132 and 152 are formed and the reference substrate 150 is also magnified by 1 / 2θ times in the moire fringes 191 formed by the intersecting periodic patterns 132 and 152.

Therefore, the pattern period of the moire fringes 191 is expressed by the following formula 1.
Distortion of periodic pattern 132 (distortion of substrate 130) / period of periodic pattern 152 = distortion of moire fringe 191 / period of moire fringe 191 Formula 1
Here, if the processing limit of the fringe analysis program that can be executed in the image processing apparatus 180 is about 1/50 of the pattern period of the moire fringes 191, the pitch of the periodic pattern 152 is set to 5 μm or less. A strain of 1 μm can be detected.

  On the other hand, if the diameter of the substrate 130 is 200 mm, about 10 moire fringes 191 can be generated at a pitch of 20 mm by setting the crossing angle of the periodic patterns 132 and 152 to 26 seconds. On the other hand, if the imaging device 170 includes an imaging device with 500 pixels per line, 50 pixels can be filled for each of the 10 moire fringes 191. In this case, 1/50 of the pattern period corresponds to one pixel of the image sensor, and a resolution capable of effectively detecting the moire fringes 191 is obtained. This is because the distortion of the periodic pattern 132 having a pitch of 5 μm is detected from the moire fringes 191 having a pitch of 20 mm, and the distortion is measured by enlarging the distortion by 4000 times.

  FIG. 12 is a diagram illustrating another example of the periodic pattern 132 formed on the substrate 130. As shown in FIG. 12A, the substrate 130 has a silicon wafer 134 and a periodic pattern 132 formed on the upper surface of the silicon wafer 134. The periodic pattern 132 includes a plurality of line patterns parallel to the orientation flat 136.

 As shown in FIG. 12B, the substrate 130 also has a periodic pattern 132 formed on the lower surface of the silicon wafer 134. The periodic pattern 132 includes a plurality of line patterns orthogonal to the orientation flat 136.

  As described above, the pattern forming step of forming the periodic pattern 132 on the substrate 130 may include a step of forming the periodic pattern 132 on the front surface and the back surface of the substrate 130, respectively. In addition, the observation stage may be performed on the front surface and the back surface of the substrate 130, respectively. As a result, the strain can be individually measured for the front surface and the back surface of the substrate 130. Furthermore, in the example shown in FIG. 12, the periodic patterns 132 formed on the front surface and the back surface of the substrate 130 are orthogonal to each other, but instead, the periodic patterns intersecting each other at an angle other than orthogonal, or The periodic patterns parallel to each other may be formed on the front surface and the back surface of the substrate 130, respectively.

  FIG. 13 is a diagram illustrating another periodic pattern 152 formed on the reference substrate 150. The reference substrate 150 is prepared corresponding to the substrate 130 on which the periodic pattern 132 is formed on both sides as shown in FIG.

  The reference substrate 150 includes a rectangular glass substrate 154 and a lattice-like periodic pattern 152 formed in parallel to each side thereof. The lattice-shaped periodic pattern 152 has periodicity in two directions orthogonal to each other. Thus, moire fringes 191 can be generated using the common periodic pattern 152 of one reference substrate 150 on both the front and back of the substrate 130 having the periodic pattern 132 on the front and back shown in FIG.

  Thus, the reference substrate 150 may have two sets of periodic patterns that intersect each other. Thereby, the distortion of the substrate 130 having the different periodic patterns 132 can be measured using the single reference substrate 150.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. In addition, it will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. Furthermore, it is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

2 is a cross-sectional view schematically showing the structure of the strain measuring device 100. FIG. 5 is a diagram illustrating an example of a periodic pattern 152 formed on a reference substrate 150. FIG. It is a flowchart which shows the procedure of the distortion measuring device method. It is a figure which shows an example of the periodic pattern 132 formed in the board | substrate 130. FIG. 3 is a diagram illustrating a method for positioning a substrate 130 in the strain measuring apparatus 100. FIG. 3 is a diagram illustrating a method for positioning a reference substrate 150 in the strain measuring apparatus 100. FIG. It is a figure which shows the image 192 displayed on the image display apparatus 190. FIG. It is a figure which shows the other image 192 displayed on the image display apparatus 190. FIG. It is a figure which shows the structure of the heating-pressing apparatus 200 typically. It is a figure which shows the image 192 displayed on the image display apparatus 190 after a process. It is a figure which shows the other image 192 displayed on the image display apparatus 190 after a process. It is a figure which shows the other example of the periodic pattern 132 formed in the board | substrate 130. FIG. It is a figure which shows the other example of the periodic pattern 152 formed in the reference board | substrate 150. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Strain measuring device, 110 Base, 112 Cover, 120 Substrate holding part, 121, 141 Contact member, 122 Tilt stage, 123, 143 Butting member, 124 Lifting stage, 126 Rotating stage, 130 Substrate, 131 Wafer, 132, 152 periodic patterns, 134 wafers, 136 orientation flats, 140 reference substrate holders, 142 columns, 150 reference substrates, 154 glass substrates, 160 illumination units, 170 imaging devices, 180 image processing devices, 190 image display devices, 191 stripes, 192 Image, 193 Deformation pattern, 200 Heating and pressing device, 210 Press, 220 Wafer holder, 230 Heating unit

Claims (11)

A pattern forming step of forming a periodic pattern having a certain period before processing is performed on a substrate on which a plurality of elements are formed;
A reference substrate preparation step of preparing a reference substrate on which a periodic pattern having a constant period is formed;
An observation step of superimposing the substrate on which the processing has been performed on the reference substrate and observing fringes caused by overlapping of periodic patterns;
A strain measurement method comprising: measuring a strain of the substrate from an observation result in the observation step.   The strain measurement method according to claim 1, wherein the process includes a pressurizing process executed by a pressurizing apparatus that pressurizes the substrate with the reference substrate.   The strain measurement method according to claim 2, wherein the pressurizing process is performed with a constant angle formed by an orientation flat of the substrate loaded in the pressurizing apparatus with respect to the pressurizing apparatus.   The strain measurement method according to any one of claims 1 to 3, wherein the periodic pattern includes a plurality of linear patterns having a certain angle with respect to an orientation flat of the substrate. The observation step includes
A pre-observation step of observing fringes caused by the overlapping of the periodic patterns by superimposing the substrate on the reference substrate before processing on the substrate is performed;
The measurement step includes a detection step of comparing the fringes observed in the previous observation step with the fringes observed after the processing is executed and detecting distortion generated in the substrate by the processing. The strain measurement method according to any one of claims 1 to 4. The pattern forming step includes the step of forming the periodic pattern on the front surface and the back surface of the substrate, respectively.
The strain measurement method according to any one of claims 1 to 5, wherein the observation step is performed on each of a front surface and a back surface of the substrate.   The strain measurement method according to claim 6, wherein the periodic patterns respectively formed on the front surface and the back surface of the substrate are formed in directions intersecting each other.   The strain measurement method according to claim 7, wherein the reference substrate has two sets of the periodic patterns intersecting each other.   The observation step includes a re-observation step of observing other fringes generated by changing an angle at which the periodic pattern of the substrate and the periodic pattern of the reference substrate intersect. The strain measurement method according to one item. The observation step is an imaging step in which the substrate is photographed by an imaging device having an imaging plane inclined with respect to the surface of the substrate;
The distortion measurement method according to claim 1, further comprising: a correction step of correcting an image obtained by the imaging device into an image appearing on a coupling surface parallel to the surface of the substrate. A substrate holding part for holding a substrate on which a plurality of elements are formed, in which a periodic pattern having a certain period is formed;
A reference substrate holding unit that holds a reference substrate having a periodic pattern formed at a constant period, overlaid on the substrate;
In the overlapping substrate and the reference substrate, an imaging device that captures stripes generated by the overlapping of the periodic patterns;
A strain measurement device that measures strain of the substrate based on the shape of the stripes captured by the imaging device.

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