Method for measuring thickness of laminate, apparatus for measuring thickness of laminate, and method for manufacturing laminate

Abstract

One example of the present disclosure relates to a method for measuring the thickness of a laminate 1. When measuring the thickness of a laminate 1, it is desirable to reduce variation in the measured thickness of the laminate 1. In the present disclosure, a first surface 1a of a laminate 1 is irradiated with a first laser beam L1 and a second surface 1b of the laminate 1 is irradiated with a second laser beam L2 while scanning the first laser beam L1 and the second laser beam L2 in a direction that is oblique with respect to the mesh direction of a glass cloth 21. Furthermore, the thickness of the laminate 1 is measured on the basis of irradiation results of the first laser beam L1 and the second laser beam L2 that were scanned in the abovementioned direction. Even if there are variations in the protrusion height and recess depth occurring in the mesh direction of the glass cloth, scanning the first laser beam L1 and the second laser beam L2 in the abovementioned oblique direction facilitates the accommodation of changes in the protrusion height and recess depth. Thereby, variation in the measured thickness of the laminate 1 can be reduced.

Description

Method for Measuring Thickness of Laminate, Thickness Measuring Apparatus for Laminate, and Method for Manufacturing Laminate

[0001] The present disclosure relates to a method for measuring the thickness of a laminate, a thickness measuring apparatus for a laminate, and a method for manufacturing a laminate.

[0002] In recent years, with the rapid advancement of high functionality of electronic devices represented by AI / HPC and the like, the size and density of semiconductor packages have been rapidly increasing. The package structure is not limited to the high density of surface mounting, and the package structure and mounting process are becoming more complex and diverse, such as inorganic (silicon) or organic interposer (Bridge die / RDL) technology, 2.xD mounting using the same, and 3D mounting (HBM / Chiplet) technology using TSV. For example, Resonac Co., Ltd. is mainly based on the "Packaging Solution Center" and is developing technologies for next-generation semiconductor packaging processes from the perspective of customers (semiconductor manufacturers) by combining mounting processes and materials.

[0003] In such a semiconductor package field, the thickness of one component of the semiconductor package may be measured. For example, Patent Document 1 discloses a method for measuring the thickness of a measurement object using two laser displacement meters arranged in a direction sandwiching both sides of the measurement object.

[0004] Japanese Patent Application Laid-Open No. 2013-72860

[0005] Examples of one component of the semiconductor package described above include a laminate including a glass cloth formed in a mesh shape by weaving glass fibers and a resin impregnated in the glass cloth. In such a laminate, since the glass cloth is formed by weaving glass fibers, irregularities occur along the mesh direction. And the amount of these irregularities varies for each glass fiber adjacent to each other in the mesh direction.

[0006] When applying the above-described thickness measurement method to laminates with such irregularities, a configuration is sometimes adopted in which two laser displacement sensors are coaxial and the laser beams emitted from each sensor are scanned along the mesh direction of the glass cloth. However, during the scanning of the laser beams, the axes of the two laser beams may become misaligned. As mentioned above, the amount of irregularity in the glass cloth differs for each adjacent glass fiber in the mesh direction, so when the axes of the two laser displacement sensors become misaligned, the laser beams are irradiated at positions with different amounts of irregularity. In this case, there is a risk of variation in the thickness of the laminate being measured. Therefore, a method for measuring the thickness of laminates that can reduce this variation in the measured thickness is desired.

[0007] This disclosure aims to provide a method for measuring the thickness of a laminate, a device for measuring the thickness of a laminate, and a method for manufacturing a laminate, which can reduce variations in the thickness of the laminate being measured.

[0008] [1] The present disclosure provides a method for measuring the thickness of a laminate, which includes, as one side, a first surface and a second surface located opposite to the first surface. In this method for measuring the thickness of a laminate, the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together, and a resin impregnated into the glass cloth. This thickness measurement method comprises the steps of: irradiating the first surface with the first laser beam and the second surface with the second laser beam while scanning the first and second laser beams in a direction inclined with respect to the mesh direction of the glass cloth in a predetermined measurement section; and calculating the thickness of the laminate based on the irradiation results of the first and second laser beams.

[0009] In this laminate thickness measurement method, a first laser beam and a second laser beam are scanned in a predetermined measurement section in a direction inclined with respect to the mesh direction of the glass cloth. By scanning the first and second laser beams in the above-mentioned direction, the first and second laser beams are irradiated over multiple glass fibers that are adjacent to each other in the mesh direction. Therefore, even if the axes of the first and second laser beams are misaligned and the first and second laser beams are irradiated at positions with different amounts of unevenness, the scanning direction of the first and second laser beams is inclined with respect to the mesh direction of the glass cloth, so the changes in the amount of unevenness are easily absorbed. As a result, this laminate thickness measurement method can reduce the variation in the thickness of the laminate being measured.

[0010] [2] In the method for measuring the thickness of the laminate described in [1] above, in the irradiation step, the first laser beam and the second laser beam may be scanned in a direction that is inclined at 30° to 60° with respect to the mesh direction of the glass cloth. In this case, even if the first laser beam and the second laser beam are irradiated at positions with different amounts of unevenness due to the axis of the first laser beam and the axis of the second laser beam being misaligned, the change in the amount of unevenness is absorbed more easily. Therefore, the variation in the thickness of the laminate being measured can be reduced even further.

[0011] [3] In the method for measuring the thickness of the laminate described in [2] above, in the irradiation step, the first laser beam and the second laser beam may be scanned in a direction that is inclined at 40° to 50° with respect to the mesh direction of the glass cloth. In this case, even if the first laser beam and the second laser beam are irradiated at positions with different amounts of unevenness due to the axis of the first laser beam and the axis of the second laser beam being misaligned with each other, the change in the amount of unevenness is more reliably absorbed. Therefore, variations in the thickness of the laminate being measured can be reduced more reliably.

[0012] [4] In any of the laminate thickness measurement methods described in [1] to [3] above, the predetermined measurement section may have a length greater than the mesh size of the glass cloth in a direction inclined with respect to the mesh direction of the glass cloth. In this case, the first laser beam and the second laser beam can be reliably irradiated across multiple glass fibers that are adjacent to each other in the mesh direction. As a result, variations in the thickness of the laminate being measured can be reliably reduced.

[0013] [5] In any of the laminate thickness measurement methods described in [1] to [3] above, the predetermined measurement section may have a length of 0.7 mm or more in a direction inclined with respect to the mesh direction of the glass cloth. In this case, the first laser beam and the second laser beam can be reliably irradiated across multiple glass fibers that are adjacent to each other in the mesh direction. As a result, variations in the thickness of the measured laminate can be reliably reduced.

[0014] [6] In another aspect, the present disclosure provides an apparatus for measuring the thickness of a laminate including a first surface and a second surface located opposite to the first surface. In this laminate thickness measuring apparatus, the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together, and a resin impregnated into the glass cloth. The laminate thickness measuring apparatus comprises a first measuring instrument that irradiates a first laser beam, a second measuring instrument that irradiates a second laser beam, a control unit that controls the first and second measuring instruments, and a measuring unit that measures the thickness of the laminate. The control unit irradiates the first surface with the first laser beam and the second surface with the second laser beam while scanning the first and second laser beams in a direction inclined with respect to the mesh direction of the glass cloth within a predetermined measurement section. The measuring unit calculates the thickness of the laminate based on the irradiation results of the first and second laser beams.

[0015] In this laminate thickness measuring device, a first laser beam and a second laser beam are scanned in a predetermined measurement section in a direction inclined with respect to the mesh direction of the glass cloth. By scanning the first and second laser beams in the above-described direction, the first and second laser beams are irradiated across multiple glass fibers that are adjacent to each other in the mesh direction. Therefore, even if the axes of the first measuring instrument and the second measuring instrument are misaligned and the first and second laser beams are irradiated at positions with different amounts of unevenness, the scanning direction of the first and second laser beams is inclined with respect to the mesh direction of the glass cloth, so the changes in the amount of unevenness are easily absorbed. As a result, this laminate thickness measuring device can reduce the variation in the thickness of the laminate being measured.

[0016] [7] In the laminate thickness measuring device described in [6] above, the control unit may scan the first laser beam and the second laser beam in a direction inclined at 30° to 60° with respect to the mesh direction of the glass cloth. In this case, even if the first laser beam and the second laser beam are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first measuring instrument and the second measuring instrument, the change in the amount of unevenness is absorbed more easily. Therefore, the variation in the thickness of the laminate being measured can be reduced even further.

[0017] [8] In the laminate thickness measuring device described in [7] above, the control unit may scan the first laser beam and the second laser beam in a direction inclined at 40° to 50° with respect to the mesh direction of the glass cloth. In this case, even if the first laser beam and the second laser beam are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first measuring instrument and the second measuring instrument, the change in the amount of unevenness is more reliably absorbed. Therefore, variations in the thickness of the laminate being measured can be reduced more reliably.

[0018] [9] In any of the laminate thickness measuring devices described in [6] to [8] above, a predetermined measuring section may have a length greater than the mesh size of the glass cloth in a direction inclined with respect to the mesh direction of the glass cloth. In this case, the first laser beam and the second laser beam can be reliably irradiated across multiple glass fibers that are adjacent to each other in the mesh direction. As a result, variations in the thickness of the laminate being measured can be reliably reduced.

[0019]

[10] In any of the laminate thickness measuring devices described in [6] to [8] above, a predetermined measuring section may have a length of 0.7 mm or more in a direction inclined with respect to the mesh direction of the glass cloth. In this case, the first laser beam and the second laser beam can be reliably irradiated across multiple glass fibers that are adjacent to each other in the mesh direction. As a result, variations in the thickness of the measured laminate can be reliably reduced.

[0020]

[11] In yet another aspect, the present disclosure provides a method for manufacturing a laminate. This method for manufacturing a laminate includes the steps of: preparing a laminate including a first surface and a second surface located opposite to the first surface, wherein the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together and a resin impregnated into the glass cloth; irradiating the first surface with the first laser beam and the second surface with the second laser beam while scanning the first and second laser beams in a direction inclined with respect to the mesh direction of the glass cloth in a predetermined measurement section; and calculating the thickness of the laminate based on the irradiation results of the first and second laser beams.

[0021] In this laminate manufacturing method, a first laser beam and a second laser beam are scanned in a predetermined measurement section in a direction inclined with respect to the mesh direction of the glass cloth. By scanning the first and second laser beams in the above-described direction, the first and second laser beams are irradiated over multiple glass fibers that are adjacent to each other in the mesh direction. Therefore, even if the axes of the first and second laser beams are misaligned and the first and second laser beams are irradiated at positions with different amounts of unevenness, the scanning direction of the first and second laser beams is inclined with respect to the mesh direction of the glass cloth, so the changes in the amount of unevenness are easily absorbed. As a result, this laminate manufacturing method can reduce variations in the thickness of the measured laminate.

[0022] According to this disclosure, it is possible to reduce variations in the thickness of the measured laminate.

[0023] Figure 1 is a perspective view showing an example of a laminate according to one embodiment. Figure 2 is a cross-sectional view of the laminate shown in Figure 1. Figure 3 is a block diagram showing the functional configuration of a thickness measuring device for a laminate according to one embodiment of the present disclosure. Figure 4 is a diagram illustrating a method for measuring the thickness of a laminate according to one embodiment of the present disclosure. Figure 5 is a diagram illustrating a method for measuring the thickness of a laminate according to one embodiment of the present disclosure. Figure 6 is a diagram illustrating a method for measuring the thickness of a laminate according to one embodiment of the present disclosure.

[0024] Hereinafter, several embodiments of this disclosure will be described in detail, with reference to the drawings as necessary. In the following description, the same or corresponding parts will be denoted by the same reference numerals, and redundant descriptions will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. When terms such as "left," "right," "front," "back," "top," "bottom," "upper," and "downward" are used in this specification, they are for illustrative purposes only and do not necessarily mean that the relative positions are permanent. Moreover, the dimensional ratios in the drawings are not limited to those shown.

[0025] In this specification, the term "layer" includes not only structures that are formed across the entire surface when observed in a plan view, but also structures that are formed in only a part of the surface. Furthermore, in this specification, the term "process" includes not only independent processes, but also processes that are not clearly distinguishable from other processes, as long as their intended function is achieved. In addition, numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively.

[0026] (Structure of the laminated board) First, an example of a laminated board according to one embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing an example of a laminated board according to one embodiment. Figure 2 is a cross-sectional view of the laminated board shown in Figure 1. As shown in Figures 1 and 2, the laminated board 1 includes a first surface 1a and a second surface 1b located on the opposite side from the first surface 1a. The laminated board 1 has a rectangular shape in plan view, for example. The laminated board 1 may have a width of 50 mm or more and 700 mm or less, or a length of 50 mm or more and 700 mm or less.

[0027] In this embodiment, the laminate 1 includes a base material 2 and a pair of metal foils 3 formed on both sides of the base material 2. In a configuration in which the laminate 1 includes a base material 2 and a pair of metal foils 3, the surfaces of the metal foils 3 formed on both sides of the base material 2 include corresponding surfaces from the first surface 1a and the second surface 1b.

[0028] As shown in Figure 2, the base material 2 includes a mesh-like glass cloth 21 and a resin 22 impregnated into the glass cloth 21. The glass cloth 21 is formed in a mesh-like manner, for example, by weaving glass fibers into it. The glass fibers include a plurality of warp threads 21a and a plurality of weft threads 21b (see Figure 6). The glass cloth 21 is, for example, a woven fabric made of a plurality of warp threads 21a and a plurality of weft threads 21b.

[0029] The warp threads 21a and weft threads 21b are aligned along mutually perpendicular directions. The direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned do not have to be mutually perpendicular. It is sufficient that the direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned intersect with each other. In the glass cloth 21, the direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned constitute the mesh direction of the glass cloth 21. That is, the mesh direction of the glass cloth 21 includes the direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned.

[0030] The base material 2 is a sheet-like material formed by impregnating glass cloth 21 with resin 22 and leaving it in a semi-cured state, or it includes an insulating layer formed by hardening this semi-cured sheet-like material through lamination and integration by heating and pressurizing. In other words, the base material 2 includes a base material that has insulating properties. Such a base material 2 is also called a "prepreg".

[0031] The resin 22 is not particularly limited, but examples include epoxy resin, phenolic resin, unsaturated imide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, triazine resin, melamine resin, etc. These may be used individually or in combination of two or more types. Among these, epoxy resin and cyanate resin are preferred from the viewpoint of moldability or electrical insulation.

[0032] From the viewpoint of conductivity, the metal foil 3 may contain copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing at least one of these metal elements. In this embodiment, the metal foil 3 contains copper and is therefore a copper foil. That is, in this embodiment, the laminate 1 is a copper-clad laminate in which copper foil is formed as the metal foil 3 on both sides of the base material 2. An insulating resin layer may be provided between the metal foil 3 and the base material 2.

[0033] (Configuration of Thickness Measuring Device) Next, with reference to Figure 3, the configuration of a thickness measuring device for laminates according to one embodiment of the present disclosure will be described. Figure 3 is a block diagram showing the functional configuration of a thickness measuring device for laminates according to one embodiment of the present disclosure. The thickness measuring device 10 is used, for example, to measure the thickness of a laminate 1 shown in Figure 1. In this embodiment, the thickness measuring device 10 includes a first measuring instrument 11, a second measuring instrument 12, a control unit 13, and a measuring unit 14, as shown in Figure 3.

[0034] The first measuring instrument 11 irradiates the object to be measured with the first laser beam L1. Specifically, the first measuring instrument 11 measures the distance between the object to be measured and the first measuring instrument 11 by irradiating the object to be measured with the first laser beam L1. The first measuring instrument 11 includes, for example, a laser displacement meter (Keyence Corporation, CL-3000 series).

[0035] When the thickness of the laminate 1 is measured by the thickness measuring device 10, the first measuring instrument 11 is positioned above the first surface 1a. The first measuring instrument 11 then irradiates the first surface 1a with the first laser beam L1. That is, the first measuring instrument 11 measures the distance between the first surface 1a and the first measuring instrument 11 by irradiating the first surface 1a with the first laser beam L1.

[0036] In this embodiment, the first measuring instrument 11 continuously irradiates the first surface 1a with the first laser beam L1. Therefore, in this embodiment, the distance between the first surface 1a and the first measuring instrument 11 is continuously measured by the first measuring instrument 11. The first measuring instrument 11 may also discretely irradiate the first surface 1a with the first laser beam L1. That is, the distance between the first surface 1a and the first measuring instrument 11 may be measured discretely by the first measuring instrument 11.

[0037] The second measuring instrument 12 irradiates a second laser beam L2. Specifically, the second measuring instrument 12 measures the distance between the object to be measured and the second measuring instrument 12 by irradiating the same object to be measured as the first measuring instrument 11 with the second laser beam L2. Similar to the first measuring instrument 11, the second measuring instrument 12 also includes, for example, a laser displacement meter (Keyence Corporation, CL-3000 series).

[0038] When the thickness of the laminated plate 1 is measured by the thickness measuring device 10, the second measuring instrument 12 is disposed above the second surface 1b. That is, when measuring the thickness of the laminated plate 1, the first measuring instrument 11 and the second measuring instrument 12 are disposed so as to sandwich the laminated plate 1 in the thickness direction of the laminated plate 1. At this time, the first measuring instrument 11 and the second measuring instrument 12 are disposed such that the irradiation position of the first laser beam L1 on the first surface 1a and the irradiation position of the second laser beam L2 on the second surface 1b completely overlap when viewed from the thickness direction of the laminated plate 1. That is, the first measuring instrument 11 and the second measuring instrument 12 are disposed such that the axes of the first laser beam L1 and the second laser beam L2 are the same. When viewed from the thickness direction of the laminated plate 1, the irradiation position of the first laser beam L1 on the first surface 1a and the irradiation position of the second laser beam L2 on the second surface 1b may at least partially overlap each other, or may not overlap each other.

[0039] Then, the second measuring instrument 12 irradiates the second surface 1b with the second laser beam L2. That is, the second measuring instrument 12 measures the distance between the second surface 1b and the second measuring instrument 12 by irradiating the second surface 1b with the second laser beam L2.

[0040] In the present embodiment, the second measuring instrument 12 measures the distance between the second surface 1b and the second measuring instrument 12 by continuously irradiating the second surface 1b with the second laser beam L2. Therefore, in the present embodiment, the distance between the second surface 1b and the second measuring instrument 12 is continuously measured by the second measuring instrument 12. The second measuring instrument 12 may irradiate the second surface 1b with the second laser beam L2 discretely. That is, the distance between the second surface 1b and the second measuring instrument 12 may be measured discretely by the second measuring instrument 12.

[0041] The control unit 13 controls the first measuring instrument 11 and the second measuring instrument 12. The control unit 13 is electrically connected to the first measuring instrument 11 and the second measuring instrument 12, and controls the irradiation position, scanning speed, and scanning direction of the first laser beam L1 and the second laser beam L2 with respect to the laminated plate 1. The scanning direction may be defined mechanically.

[0042] The control unit 13 acquires the distance between the first surface 1a and the first measuring device 11 measured by the first measuring device 11 and the distance between the second surface 1b and the second measuring device 12 measured by the second measuring device 12 at a predetermined time interval. Therefore, it can be said that the control unit 13 controls the sampling intervals of the two distances.

[0043] The predetermined time interval, that is, the sampling interval may be, for example, 10 μs or more, or may be 100 μs or more. Also, the predetermined interval may be, for example, 100000 μs or less, or may be 100000 μms or less. The control unit 13 outputs the distance between the first surface 1a and the first measuring device 11 and the distance between the second surface 1b and the second measuring device 12 acquired at the predetermined time interval to the measuring unit 14.

[0044] When the first measuring device 11 discretely irradiates the first surface 1a with the first laser beam L1 and the second measuring device 12 discretely irradiates the second surface 1b with the second laser beam L2, the control unit 13 may control the timing of irradiation of the first laser beam L1 in the first measuring device 11 and the timing of irradiation of the second laser beam L2 in the second measuring device 12. In this case, the control unit 13 may control the first measuring device 11 so that the first laser beam L1 is irradiated on the first surface 1a at a predetermined interval, and control the second measuring device 12 so that the second laser beam L2 is irradiated on the second surface 1b at the predetermined time interval. Specifically, the control unit 13 may control the operating speeds of the first measuring device 11 and the second measuring device 12 and the timing of irradiation of the first laser beam L1 and the second laser beam L2 so that the intervals between the positions where the first laser beam L1 is irradiated and the intervals between the positions where the second laser beam L2 is irradiated are uniform.

[0045] The measuring unit 14 measures the thickness of the laminate 1. The measuring unit 14 calculates the thickness of the laminate 1 based on the irradiation results of the first laser beam L1 and the second laser beam L2. In this embodiment, it can also be said that the measuring unit 14 calculates the thickness of the laminate 1 based on the measurement results of the first measuring instrument 11 and the second measuring instrument 12. The measuring unit 14 also stores the distance between the first measuring instrument 11 and the second measuring instrument 12 in the thickness direction of the laminate 1 when the first laser beam L1 and the second laser beam L2 are irradiated. In this embodiment, the thickness of the laminate 1 is calculated based on the distance between the first measuring instrument 11 and the second measuring instrument 12, the distance between the first surface 1a and the first measuring instrument 11, and the distance between the first surface 1a and the first measuring instrument 11. Details of the method for calculating the thickness of the laminate 1 will be described later.

[0046] (Method for Manufacturing Laminated Boards) Next, the method for manufacturing the laminated board 1 will be described with reference to Figures 4, 5, and 6. Figures 4, 5, and 6 are diagrams illustrating a method for measuring the thickness of a laminated board according to one embodiment of the present disclosure.

[0047] The laminate 1 can be manufactured, for example, through the following steps (a) to (c): (a) a step of preparing the laminate 1; (b) a step of irradiating the first surface 1a with a first laser beam L1 and the second surface 1b with a second laser beam L2; (c) a step of calculating the thickness of the laminate 1. The manufacturing method of the laminate 1 according to this embodiment includes a method for measuring the thickness of the laminate 1. The method for measuring the thickness of the laminate 1 includes the steps (b) and (c) described above. The method for measuring the thickness of the laminate 1 may also include step (a).

[0048] [Process (a)] Process (a) is the process of preparing the laminate 1. In process (a), first, the base material 2 is prepared. In preparing the base material 2, resin 22 is prepared and the resin 22 is impregnated into the glass cloth 21. After that, the base material 2 is formed by heating and drying in an environment of a predetermined temperature and a predetermined pressure.

[0049] In step (a), the metal foil 3 is then placed on both sides of the base material 2, and pressure is applied to both sides in the thickness direction of the base material 2 and the metal foil 3 to laminate them. When placing the metal foil 3 on both sides of the base material 2, for example, an adhesive is applied to both sides of the base material 2. The base material 2 and the metal foil 3 are then heated and dried in an environment of a predetermined temperature and a predetermined pressure. This prepares a laminated board 1 including the base material 2 and the metal foil 3 formed on both sides of the base material 2.

[0050] [Step (b)] Step (b) is a step of irradiating with a first laser beam L1 and a second laser beam L2. In step (b), first, the laminate 1 prepared in step (a) is placed on the stage S. In this embodiment, as shown in Figure 4, the laminate 1 is placed on the stage S so that the second surface 1b and the surface of the stage S are in contact. In this embodiment, the stage S is provided with a plurality of through holes H (see Figure 5), which makes it possible to irradiate the second surface 1b with the second laser beam L2. The opening width of the through holes H is, for example, 3.0 μm. The laminate 1 may also be placed on the stage S so that the first surface 1a and the surface of the stage S are in contact.

[0051] The laminated plate 1 is placed at a predetermined position on the stage S. In this embodiment, the laminated plate 1 is placed on the stage S such that, when viewed from the thickness direction of the laminated plate 1, the upper left corner is at a predetermined position on the stage S. By placing the laminated plate 1 at a predetermined position on the stage S in this way, the scanning direction of the first laser beam L1 and the second laser beam L2 can be easily controlled.

[0052] In step (b), the first measuring instrument 11 and the second measuring instrument 12 are moved to the starting point P1 (see Figure 5). The starting point P1 is the position where the measurement of the thickness of the laminate 1 begins. The position of the starting point P1 is defined, for example, by the coordinate position in a two-dimensional coordinate system on a plane along the first surface 1a and the second surface 1b. The position of the starting point P1 is stored, for example, in a memory unit (not shown) of the thickness measuring device 10. In this embodiment, the control unit 13 reads the above position of the starting point P1 from the memory unit and moves the first measuring instrument 11 and the second measuring instrument 12 to the starting point P1.

[0053] In one example, the distance between the first measuring instrument 11 and the second measuring instrument 12 may be calculated using a block gauge BG during movement to the starting point P1. The block gauge BG is positioned, for example, along the movement path from the initial positions of the first measuring instrument 11 and the second measuring instrument 12 to the starting point P1. The initial positions are, for example, outside the stage S.

[0054] The distance between the first measuring instrument 11 and the second measuring instrument 12 is calculated, for example, as follows: First, the distance between the first measuring instrument 11 and the upper surface of the block gauge BG is measured by the first measuring instrument 11, and the distance between the second measuring instrument 12 and the lower surface of the block gauge BG is measured by the second measuring instrument 12. Then, the first measuring instrument 11 and the second measuring instrument 12 output their measurement results to the measuring unit 14.

[0055] The measuring unit 14 then calculates the distance between the first measuring instrument 11 and the second measuring instrument 12 based on the thickness of the block gauge BG and the measured distance between the first measuring instrument 11 and the upper surface of the block gauge BG, and the distance between the second measuring instrument 12 and the lower surface of the block gauge BG. Specifically, the measuring unit 14 calculates the distance between the first measuring instrument 11 and the second measuring instrument 12 as the sum of the thickness of the block gauge BG and the measured distance between the first measuring instrument 11 and the upper surface of the block gauge BG, and the distance between the second measuring instrument 12 and the lower surface of the block gauge BG. The measuring unit 14 stores the calculated distance between the first measuring instrument 11 and the second measuring instrument 12 in the storage unit. In this embodiment, the control unit 13 moves the first measuring instrument 11 and the second measuring instrument 12 to the starting point P1 while maintaining the calculated distance.

[0056] As shown in Figure 5, in step (b), the control unit 13 scans the first laser beam L1 and the second laser beam L2 from the starting point P1 to the ending point P2, irradiating the first surface 1a with the first laser beam L1 and the second surface 1b with the second laser beam L2. The ending point P2 is the position where the measurement of the thickness of the laminate 1 is completed. The position of the ending point P2, like the position of the starting point P1, is defined by a coordinate position in a two-dimensional coordinate system on a plane along the first surface 1a and the second surface 1b, and is stored in a memory unit (not shown) of the thickness measuring device 10. In the example shown in Figure 5, the direction in which the first laser beam L1 and the second laser beam L2 are scanned is shown as the first direction D1, and in the following description, the above direction in which the first laser beam L1 and the second laser beam L2 are scanned may also be referred to as the first direction D1. In this embodiment, the section from the starting point P1 to the ending point P2 becomes a predetermined measurement section MS for measuring the thickness of the laminate 1.

[0057] In step (b), the control unit 13 moves the first measuring instrument 11 and the second measuring instrument 12 from the starting point P1 to the ending point P2, thereby scanning the first laser beam L1 and the second laser beam L2. As a result, the distance between the first surface 1a and the first measuring instrument 11, and the distance between the second surface 1b and the second measuring instrument 12 are measured from the starting point P1 to the ending point P2. At this time, the control unit 13 acquires the distance between the first surface 1a and the first measuring instrument 11, and the distance between the second surface 1b and the second measuring instrument 12 at the predetermined time intervals described above.

[0058] As described above, the two distances are measured while scanning the first laser beam L1 and the second laser beam L2. Therefore, acquiring these two distances at predetermined time intervals can also be said to be acquiring these two distances at predetermined distance intervals in the first direction D1. Accordingly, in step (b), the control unit 13 can also be said to acquire the distance between the first surface 1a and the first measuring instrument 11 and the distance between the second surface 1b and the second measuring instrument 12 at each of a plurality of positions in the first direction D1 from the starting point P1 to the ending point P2.

[0059] In step (b), the first direction D1 is a direction inclined with respect to the mesh direction of the glass cloth 21. That is, in step (b), the control unit 13 scans the first laser beam L1 and the second laser beam L2 in a direction inclined with respect to the mesh direction of the glass cloth 21 within the measurement section MS, irradiating the first surface 1a with the first laser beam L1 and the second surface 1b with the second laser beam L2.

[0060] As described above, the mesh direction of the glass cloth 21 includes the direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned. As shown in Figure 6, in step (b), the first direction D1 is a direction that is inclined with respect to both the direction in which the warp threads 21a are aligned and the direction in which the weft threads 21b are aligned.

[0061] In the example shown in Figure 6, the direction in which the warp threads 21a are aligned is shown as the second direction D2, and the direction in which the weft threads 21b are aligned is shown as the third direction D3. Therefore, in the example shown in Figure 6, the first direction D1 is a direction that is inclined with respect to both the second direction D2 and the third direction D3. Furthermore, in the following explanation, the direction in which the warp threads 21a are aligned may be referred to as the second direction D2, and the direction in which the weft threads 21b are aligned may be referred to as the third direction D3. Note that in Figure 6, the metal foil 3 and other elements are omitted from the illustration in order to clarify the relationship between the first direction D1, the second direction D2, and the third direction D3.

[0062] In step (b), it is preferable that the control unit 13 scans the first laser beam L1 and the second laser beam L2 in a direction inclined at 30° to 60° with respect to the mesh direction of the glass cloth 21. Furthermore, in step (b), it is more preferable that the control unit 13 scans the first laser beam L1 and the second laser beam L2 in a direction inclined at 40° to 50° with respect to the mesh direction of the glass cloth 21. That is, the angle between the first direction D1 and the second direction D2 and third direction D3 is preferably 30° to 60°, and more preferably 40° to 50°.

[0063] In this disclosure, the "angle between the first direction D1 and the second and third directions D2 and D3" is expressed as an absolute value and refers to both positive and negative angles. For example, the angle between the first direction D1 and the second and third directions D2 and D3 being 30° or more and 60° or less includes the angle being -60° or more and -30° or less. The first direction D1 only needs to be inclined with respect to both the second and third directions D2 and D3, and the angle between the first direction D1 and the second direction D2 and the angle between the first direction D1 and the third direction D3 may be the same or different from each other.

[0064] The measurement interval MS may be set based on the mesh size of the glass cloth 21. The mesh size of the glass cloth 21 is defined, for example, by the spacing between adjacent warp threads 21a in the second direction D2 and the spacing between adjacent weft threads 21b in the third direction D3. Specifically, the mesh of the glass cloth 21 is represented by a rectangle where the length in the second direction D2 is the spacing between adjacent warp threads 21a, and the length in the third direction D3 is the spacing between adjacent weft threads 21b. The mesh size of the glass cloth 21 is defined, for example, by the length of the diagonal of the rectangle. The mesh size of the glass cloth 21 may be, for example, 0.05 mm or more and 2 mm or less.

[0065] In this embodiment, as shown in Figure 6, the length L of the measurement section MS in the first direction D1 is greater than the mesh size of the glass cloth 21. That is, in this embodiment, the measurement section MS has a length L greater than the mesh size of the glass cloth 21 in the first direction D1. The length L is defined, for example, by the distance between the starting point P1 and the ending point P2 in the first direction D1. In this embodiment, the length L is 0.7 mm or more. The length L may be 1.0 mm or more.

[0066] [Step (c)] Step (c) is a step in which the thickness of the laminate 1 is calculated. In step (c), the measuring unit 14 calculates the thickness of the laminate 1 based on the irradiation results of the first laser beam L1 and the second laser beam L2. In this embodiment, the measuring unit 14 calculates the thickness of the laminate 1 as follows, for example. First, the measuring unit 14 reads the distance between the first measuring instrument 11 and the second measuring instrument 12 stored in the memory unit. Next, the measuring unit 14 measures the thickness of the laminate 1 at each of a plurality of positions in the first direction D1. That is, the measuring unit 14 measures the thickness of the laminate 1 using the distance between the first surface 1a and the first measuring instrument 11 and the distance between the second surface 1b and the second measuring instrument 12, which are acquired at the predetermined time intervals. Specifically, the measuring unit 14 calculates the difference between the sum of the distance between the first measuring instrument 11 and the first surface 1a and the distance between the second measuring instrument 12 and the second surface 1b, and the distance between the first measuring instrument 11 and the second measuring instrument 12, at each of the multiple positions in the first direction D1 of the laminated board 1. The measuring unit 14 then calculates the thickness of the laminated board 1 using a statistical value of the difference calculated at each of the multiple positions in the first direction D1 of the laminated board 1. The statistical value may be, for example, the average value or the median value.

[0067] As described above, in the thickness measurement method for the laminate 1 according to this embodiment, the first laser beam L1 and the second laser beam L2 are scanned in the measurement section MS in a first direction D1 that is inclined with respect to the second direction D2 and the third direction D3, which are the mesh directions of the glass cloth 21. As the first laser beam L1 and the second laser beam L2 are scanned in the first direction D1, the first laser beam L1 and the second laser beam L2 are irradiated over a plurality of warp threads 21a adjacent to each other in the second direction D2, and a plurality of weft threads 21b adjacent to each other in the third direction D3. Therefore, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the axis of the first laser beam L1 and the axis of the second laser beam L2 being misaligned, the changes in the amount of unevenness are easily absorbed because the scanning direction of the first laser beam L1 and the second laser beam L2 (first direction D1) is inclined with respect to the second direction D2 and the third direction D3. As a result, the thickness measurement method for the laminated board 1 according to this embodiment can reduce variations in the thickness of the laminated board 1 being measured.

[0068] In the method for measuring the thickness of the laminate 1, the scanning direction (first direction D1) of the first laser beam L1 and the second laser beam L2 is inclined at an angle of 30° to 60° with respect to the second direction D2 and the third direction D3. In this case, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first laser beam L1 and the second laser beam L2, the changes in the amount of unevenness are more easily absorbed. Therefore, the variation in the thickness of the laminate 1 being measured can be further reduced.

[0069] Furthermore, in the method for measuring the thickness of the laminate 1, the scanning direction (first direction D1) of the first laser beam L1 and the second laser beam L2 is inclined at an angle of 40° to 50° with respect to the second direction D2 and the third direction D3. In this case, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first laser beam L1 and the second laser beam L2, the changes in the amount of unevenness are absorbed more reliably. Therefore, variations in the thickness of the laminate 1 being measured can be reduced more reliably.

[0070] In the method for measuring the thickness of the laminate 1, the measurement section MS has a length L greater than the mesh size of the glass cloth 21 in the first direction D1. In this case, the first laser beam L1 and the second laser beam L2 can be reliably irradiated over a plurality of warp threads 21a adjacent to each other in the second direction D2, and a plurality of weft threads 21b adjacent to each other in the third direction D3. As a result, variations in the thickness of the laminate 1 being measured can be reliably reduced.

[0071] In the method for measuring the thickness of the laminate 1, the measurement section MS has a length L of 0.7 mm or more in the first direction D1. In this case, it is possible to reliably irradiate multiple warp threads 21a adjacent to each other in the second direction D2, and multiple weft threads 21b adjacent to each other in the third direction D3, with the first laser beam L1 and the second laser beam L2. As a result, variations in the thickness of the laminate 1 being measured can be reduced.

[0072] When measuring the thickness of the laminate 1, it is sometimes employed to irradiate the first surface 1a with the first laser beam L1 and the second surface 1b with the second laser beam L2 without scanning the first laser beam L1 and the second laser beam L2. However, in this case, the thickness of the laminate 1 is measured only at specific locations, so variations in the measured thickness of the laminate 1 are likely to occur. On the other hand, in the method for measuring the thickness of the laminate 1 according to this embodiment, the first laser beam L1 and the second laser beam L2 are scanned as described above, and the thickness of the laminate 1 is calculated as a statistical value. Therefore, in the method for manufacturing the laminate 1 according to this embodiment, it is possible to reduce variations in the measured thickness of the laminate 1 compared to the case in which the thickness of the laminate 1 is measured without scanning the first laser beam L1 and the second laser beam L2.

[0073] Furthermore, when measuring the thickness of the laminate 1, instead of using the first measuring instrument 11 and the second measuring instrument 12, a contact-type thickness measuring instrument may be brought into contact with the first surface 1a or the second surface 1b to measure the thickness of the laminate 1. In this case, when the contact-type thickness measuring instrument is brought into contact with the first surface 1a or the second surface 1b, distortion may occur in the laminate 1. If distortion occurs in the laminate 1 when measuring the thickness, this distortion can be a factor in the variation of the thickness of the laminate 1 being measured. On the other hand, in the method for measuring the thickness of the laminate 1 according to this embodiment, the first laser beam L1 is irradiated onto the first surface 1a and the second laser beam L2 is irradiated onto the second surface 1b, so distortion of the laminate 1 is less likely to occur.

[0074] Furthermore, when using the above-mentioned contact-type thickness measuring instrument, variations occur in the thickness of the laminated board 1 measured depending on the surface roughness of the first surface 1a or the second surface 1b that the thickness measuring instrument contacts. On the other hand, when the first laser beam L1 is irradiated onto the first surface 1a and the second laser beam L2 is irradiated onto the second surface 1b, the thickness of the laminated board 1 measured is less affected by the surface roughness of the first surface 1a or the second surface 1b. Therefore, in the manufacturing method of the laminated board 1 according to this embodiment, variations in the thickness of the laminated board 1 measured can be reduced compared to when the above-mentioned contact-type thickness measuring instrument is used.

[0075] In the laminate thickness measuring device 10 according to this embodiment, in the measurement section MS, the first laser beam L1 and the second laser beam L2 are scanned in a first direction D1 that is inclined with respect to the second direction D2 and the third direction D3, which are the mesh directions of the glass cloth 21. As the first laser beam L1 and the second laser beam L2 are scanned in the first direction D1, the first laser beam L1 and the second laser beam L2 are irradiated over a plurality of warp threads 21a adjacent to each other in the second direction D2, and a plurality of weft threads 21b adjacent to each other in the third direction D3. Therefore, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first measuring instrument 11 and the second measuring instrument 12, the changes in the amount of unevenness are easily absorbed because the scanning direction of the first laser beam L1 and the second laser beam L2 (first direction D1) is inclined with respect to the second direction D2 and the third direction D3. As a result, the laminate thickness measuring device 10 according to this embodiment can reduce variations in the thickness of the laminate 1 being measured.

[0076] In the laminate thickness measuring device 10, the control unit 13 scans the first laser beam L1 and the second laser beam L2 such that the scanning direction (first direction D1) of the first laser beam L1 and the second laser beam L2 is inclined at an angle of 30° to 60° with respect to the second direction D2 and the third direction D3. In this case, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first measuring instrument 11 and the second measuring instrument 12, the changes in the amount of unevenness are absorbed more effectively. Therefore, variations in the thickness of the laminate 1 being measured can be further reduced.

[0077] Furthermore, in the laminate thickness measuring device 10, the control unit 13 scans the first laser beam L1 and the second laser beam L2 such that the scanning direction (first direction D1) of the first laser beam L1 and the second laser beam L2 is inclined at an angle of 40° to 50° with respect to the second direction D2 and the third direction D3. In this case, even if the first laser beam L1 and the second laser beam L2 are irradiated at positions with different amounts of unevenness due to the misalignment of the axes of the first measuring instrument 11 and the second measuring instrument 12, the changes in the amount of unevenness are absorbed more reliably. Therefore, variations in the thickness of the laminate 1 being measured can be reduced more reliably.

[0078] In the laminate thickness measuring device 10, the measurement section MS has a length L greater than the mesh size of the glass cloth 21 in the first direction D1. In this case, the first laser beam L1 and the second laser beam L2 can be reliably irradiated over a plurality of warp threads 21a adjacent to each other in the second direction D2, and a plurality of weft threads 21b adjacent to each other in the third direction D3. As a result, variations in the thickness of the laminate 1 being measured can be reliably reduced.

[0079] In the laminate thickness measuring device 10, the measurement section MS has a length L of 0.7 mm or more in the first direction D1. In this case, the first laser beam L1 and the second laser beam L2 can be reliably irradiated over a plurality of warp threads 21a adjacent to each other in the second direction D2, and a plurality of weft threads 21b adjacent to each other in the third direction D3. As a result, variations in the thickness of the laminate 1 being measured can be reliably reduced.

[0080] The manufacturing method of the laminated board 1 according to this embodiment includes the method for measuring the thickness of the laminated board 1 as described above. Therefore, according to the manufacturing method of the laminated board 1 according to this embodiment, it is possible to reduce the variation in the thickness of the laminated board 1 being measured.

[0081] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples. Examples 1 to 4 and Comparative Examples 1 to 4 below were tested to clarify the relationship between the scanning direction of the first laser beam L1 and the second laser beam L2 and the variation in the thickness of the laminated plate 1 being measured.

[0082] [Example 1] In Example 1, a first copper-clad laminate was prepared, corresponding to the laminate 1 according to the above-described embodiment, and including a first surface and a second surface located on the opposite side of the first surface. The first copper-clad laminate included a base material and copper foil formed on both sides of the base material. The base material included a glass cloth formed in a mesh-like structure by weaving glass fibers and a resin impregnated into the glass cloth. The glass cloth formed in a mesh-like structure was a woven fabric consisting of multiple warp threads and multiple weft threads whose aligned directions are perpendicular to each other. Furthermore, in Example 1, a second copper-clad laminate having the same configuration as the first copper-clad laminate was also prepared.

[0083] In Example 1, the first laser beam L1 was irradiated onto the first surface of the first copper-clad laminate and the second laser beam L2 was irradiated onto the second surface of the first copper-clad laminate while scanning the first laser beam L1 and the second laser beam L2 in a direction inclined at 30° with respect to the direction inclined with respect to the mesh direction of the glass cloth. Here, the length L of the measurement section MS was 1.0 mm. Then, the thickness of the first copper-clad laminate was measured based on the irradiation results of the first laser beam L1 and the second laser beam L2. The method for measuring the thickness of the first copper-clad laminate was the same as the method for measuring the thickness of the laminate 1 according to the above embodiment.

[0084] Then, without changing the position of the measurement section MS, i.e., the positions of the start point P1 and the end point P2, the thickness of the first copper-clad laminate described above was measured 30 times, and the CV value of the measured thickness of the first copper-clad laminate was calculated. The above CV value was the value obtained by dividing the standard deviation of the measured thickness of the first copper-clad laminate by the average of the thicknesses of the first copper-clad laminate over 30 measurements. Furthermore, the CV value for the second copper-clad laminate was calculated in the same manner as for the first copper-clad laminate.

[0085] [Example 2] In Example 2, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 and the second laser beam L2 were scanned in a direction inclined at 45° with respect to the direction inclined with respect to the mesh direction of the glass cloth.

[0086] [Example 3] In Example 3, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 and the second laser beam L2 were scanned in a direction inclined at 60° with respect to the direction inclined with respect to the mesh direction of the glass cloth.

[0087] [Example 4] In Example 4, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 and the second laser beam L2 were scanned in a direction inclined at -45° with respect to the direction inclined with respect to the mesh direction of the glass cloth.

[0088] [Comparative Example 1] In Comparative Example 1, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 and the second laser beam L2 were scanned along the direction in which multiple weft threads were aligned within the mesh direction of the glass cloth. That is, in Comparative Example 1, the angle between the scanning direction of the first laser beam L1 and the second laser beam L2 and the mesh direction of the glass cloth was 0°.

[0089] [Comparative Example 2] In Comparative Example 2, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 and the second laser beam L2 were scanned along the direction in which multiple warp threads were aligned within the mesh direction of the glass cloth. That is, in Comparative Example 1, the angle between the scanning direction of the first laser beam L1 and the second laser beam L2 and the mesh direction of the glass cloth was 90°.

[0090] [Comparative Example 3] In Comparative Example 3, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that the first laser beam L1 was irradiated onto the first surface of the first copper-clad laminate and the second surface of the first copper-clad laminate and the second laser beam L2 was irradiated onto the second surface of the first copper-clad laminate and the second copper-clad laminate without scanning the first laser beam L1 and the second laser beam L2.

[0091] [Comparative Example 4] In Comparative Example 4, the CV values ​​of the first copper-clad laminate and the second copper-clad laminate were calculated in the same manner as in Example 1, except that a contact-type thickness measuring instrument was brought into contact with the first surface of the first copper-clad laminate and the second copper-clad laminate to measure the thickness of the first copper-clad laminate and the second copper-clad laminate.

[0092] The calculation results for Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below. In Table 1, "Angle" indicates the angle between the scanning direction of the first laser beam L1 and the second laser beam L2 and the mesh direction of the glass cloth, the first CV value indicates the CV value of the first copper-clad laminate, and the second CV value indicates the CV value of the second copper-clad laminate.

[0093] Here, in measuring the thickness of the copper-clad laminate, the CV value is 4.0 × 10 －５ The following is desired: In measuring the thickness of copper-clad laminates, the CV value should be 4.0 × 10 －５ The variation in the thickness of the measured copper-clad laminate can be said to have been reduced if the following conditions are met. Therefore, when evaluating the variation in thickness measured in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4, both the CV value of the first copper-clad laminate and the CV value of the second copper-clad laminate are 4.0 × 10⁻⁶. －５ The following conditions are met: The product is evaluated as "Good (A)" and at least one of the CV values ​​of the first copper-clad laminate and the second copper-clad laminate is 4.0 × 10 －５ If the value was greater than the given value, it was evaluated as "Unacceptable (F)".

[0094] In Examples 1, 2, 3, and 4, both the first CV value and the second CV value were 4.0 × 10⁻⁶. －５ Examples 1, 2, 3, and 4 were evaluated as "A" because the following conditions were met. On the other hand, in Comparative Example 1, the first CV value was 4.0 × 10 －５ Although the following was observed, the second CV value was 4.0 × 10 －５ Because it was larger than , Comparative Example 1 was evaluated as "F". In Comparative Examples 2, 3, and 4, both the first CV value and the second CV value were 4.0 × 10 －５Because they were larger than the target value, Comparative Examples 2, 3, and 4 were evaluated as "F".

[0095] Thus, Examples 1 to 4, in which the first laser beam L1 and the second laser beam L2 were scanned in a direction inclined with respect to the mesh direction of the glass cloth, were evaluated as "A", while Comparative Examples 1 and 2, in which the first laser beam L1 and the second laser beam L2 were scanned in a direction along the mesh direction of the glass cloth, were evaluated as "F". Therefore, it can be seen that by scanning the first laser beam L1 and the second laser beam L2 in a direction inclined with respect to the mesh direction of the glass cloth, the variation in the thickness of the measured laminate can be reduced.

[0096] Furthermore, Comparative Example 3, in which the first laser beam L1 and the second laser beam L2 were not scanned, was evaluated as "F". Therefore, it can be seen that by scanning the first laser beam L1 and the second laser beam L2 as described above and calculating the thickness of the laminate 1 as a statistical value, the variation in the measured thickness of the laminate can be reduced compared to the case where the thickness of the laminate 1 is measured without scanning the first laser beam L1 and the second laser beam L2.

[0097] Furthermore, Comparative Example 4, which used a contact-type thickness measuring instrument, was evaluated as "F". Therefore, it can be seen that by irradiating the first surface 1a with the first laser beam L1 and the second surface 1b with the second laser beam L2, the variation in the thickness of the laminated plate 1 measured can be reduced compared to the case where the above-mentioned contact-type thickness measuring instrument is used.

[0098] Although embodiments of the present disclosure have been described above, the present invention is not limited to the embodiments described above, and modifications may be made as appropriate without departing from the spirit of the invention.

[0099] In the embodiment described above, metal foil 3 was formed on both sides of the base material 2 in the laminate 1, but metal foil 3 does not have to be formed on both sides of the base material 2. In other words, the laminate 1 does not have to contain metal foil 3.

[0100] 1...Laminate, 1a...First surface, 1b...Second surface, 10...Thickness measuring device, 11...First measuring instrument, 12...Second measuring instrument, 13...Control unit, 14...Measuring unit, 21...Glass cloth, 22...Resin, L1...First laser beam, L2...Second laser beam, MS...Measurement section, L...Length.

Claims

1. A method for measuring the thickness of a laminate including a first surface and a second surface located opposite to the first surface, wherein the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together and a resin impregnated into the glass cloth, and the method comprises the steps of: irradiating the first surface with the first laser beam and the second surface with the second laser beam while scanning the first laser beam and the second laser beam in a direction inclined with respect to the mesh direction of the glass cloth in a predetermined measurement section; and calculating the thickness of the laminate based on the irradiation results of the first laser beam and the second laser beam.

2. The method for measuring the thickness of a laminate according to claim 1, wherein in the irradiation step, the first laser beam and the second laser beam are scanned in a direction that is inclined at 30° or more and 60° or less with respect to the mesh direction of the glass cloth.

3. The method for measuring the thickness of a laminate according to claim 2, wherein in the irradiation step, the first laser beam and the second laser beam are scanned in a direction that is inclined at 40° or more and 50° or less with respect to the mesh direction of the glass cloth.

4. The method for measuring the thickness of a laminate according to any one of claims 1 to 3, wherein the predetermined measurement section has a length greater than the mesh size of the glass cloth in the direction inclined with respect to the mesh direction of the glass cloth.

5. The method for measuring the thickness of a laminate according to any one of claims 1 to 3, wherein the predetermined measurement section has a length of 0.7 mm or more in the direction inclined with respect to the mesh direction of the glass cloth.

6. A device for measuring the thickness of a laminate including a first surface and a second surface located opposite to the first surface, wherein the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together and a resin impregnated into the glass cloth, the device comprising: a first measuring instrument for irradiating a first laser beam; a second measuring instrument for irradiating a second laser beam; a control unit for controlling the first and second measuring instruments; and a measuring unit for measuring the thickness of the laminate, wherein the control unit scans the first and second laser beams in a direction inclined with respect to the mesh direction of the glass cloth within a predetermined measurement section, irradiating the first laser beam onto the first surface and the second laser beam onto the second surface, and the measuring unit calculates the thickness of the laminate based on the irradiation results of the first and second laser beams.

7. The laminate thickness measuring device according to claim 6, wherein the control unit scans the first laser beam and the second laser beam in a direction inclined at 30° or more and 60° or less with respect to the mesh direction of the glass cloth.

8. The laminate thickness measuring device according to claim 7, wherein the control unit scans the first laser beam and the second laser beam in a direction inclined at 40° or more and 50° or less with respect to the mesh direction of the glass cloth.

9. The laminate thickness measuring device according to any one of claims 6 to 8, wherein the predetermined measurement section has a length greater than the mesh size of the glass cloth in the direction inclined with respect to the mesh direction of the glass cloth.

10. The laminate thickness measuring device according to any one of claims 6 to 8, wherein the predetermined measurement section has a length of 0.7 mm or more in the direction inclined with respect to the mesh direction of the glass cloth.

11. A method for manufacturing a laminate, comprising: a step of preparing a laminate including a first surface and a second surface located opposite to the first surface, wherein the laminate includes a glass cloth formed in a mesh-like structure by weaving glass fibers together and a resin impregnated into the glass cloth; a step of irradiating the first surface with the first laser beam and the second surface with the second laser beam while scanning the first laser beam and the second laser beam in a direction inclined with respect to the mesh direction of the glass cloth in a predetermined measurement section; and a step of calculating the thickness of the laminate based on the irradiation results of the first laser beam and the second laser beam.

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