Glass substrate

Abstract

The present invention achieves both suppression of cracking and suppression of deterioration in visibility of a mark. This glass substrate (10) has a main surface (10A) and a main surface (10B). A mark is formed on the main surface (10A). When a boundary position between the main surface (10A) and an end surface (10C) is defined as a first position (PA) and a position on the main surface (10A) 1 mm inward in the radial direction from the first position (PA) is defined as a second position (PB), the second position (PB) is positioned closer to the Z1 direction side, which is the direction from the main surface (10B) toward the main surface (10A), than the first position (PA), and the distance between the first position (PA) and the second position (PB) in the Z direction, which is the direction orthogonal to the main surface (10A), is 0.102 µm to 2.01 µm inclusive.

Description

Glass substrate

[0001] This invention relates to a glass substrate.

[0002] Glass is sometimes used as a support material for semiconductor devices during the manufacturing process. For example, as shown in Patent Document 1, a mark may be formed on the surface of such a glass substrate by irradiating it with laser light and engraving it.

[0003] International Publication No. 2018 / 150759

[0004] In such glass substrates, it is necessary to achieve both crack prevention and prevention of reduced visibility of the markings.

[0005] The present invention aims to achieve both the suppression of cracking and the suppression of the reduction in the visibility of the mark.

[0006] The glass substrate according to this disclosure is a glass substrate having a first main surface and a second main surface, wherein a mark is formed on the first main surface, and the boundary position between the first main surface and the end surface is defined as the first position, and the position on the first main surface 1 mm radially inward from the first position is defined as the second position, wherein the second position is located on the first direction side, which is the direction from the second main surface toward the first main surface, than the first position, and the distance between the first position and the second position in the thickness direction of the glass substrate is 0.102 μm or more and 2.01 μm or less.

[0007] According to the present invention, it is possible to achieve both the suppression of cracking and the suppression of the reduction in the visibility of the mark.

[0008] Figure 1 is a schematic diagram of a glass substrate according to the embodiment. Figure 2 is a schematic diagram of an example of a mark. Figure 3 is a schematic enlarged view of a portion of the glass substrate where dots are formed. Figure 4 is a cross-sectional view taken along line A-A in Figure 3. Figure 5 is a schematic cross-sectional view of the glass substrate according to this embodiment. Figure 6 is a flowchart showing the manufacturing method of the glass substrate according to the embodiment.

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited to these embodiments, and if there are multiple embodiments, they may be constructed by combining these embodiments. Numerical values ​​are rounded to the nearest whole number.

[0010] (Glass Substrate) Figure 1 is a schematic diagram of the glass substrate according to this embodiment. The glass substrate 10 according to this embodiment is used as a glass substrate for the manufacture of semiconductor packages and can be said to be a glass substrate that supports semiconductor devices. More specifically, the glass substrate 10 is a support glass substrate for manufacturing using fan-out wafer-level package (FOWLP) technology, and for example, if the glass substrate 10 is rectangular, it is a support glass substrate for the manufacture of fan-out panel-level package (FOLP). However, the use of the glass substrate 10 is not limited to supporting semiconductor devices or manufacturing FOWLP or FOPLP, but is arbitrary, and it may be a glass substrate used to support any component. It may also be glass or crystallized glass that is processed into any product, such as a cover glass for an image sensor or a substrate for a semiconductor device.

[0011] As shown in Figure 1, the glass substrate 10 is a plate-shaped member having one main surface 10A (first main surface), one main surface 10B (second main surface) opposite to the main surface 10A, and an end surface 10C (side surface) connecting the main surfaces 10A and 10B. The glass substrate 10 has a circular disc shape when viewed in plan, that is, when viewed from a direction perpendicular to the main surface 10A. In other words, the glass substrate 10 has a wafer shape. The glass substrate 10 may also have a notch N formed on its outer periphery, resulting in a shape where a portion of the circular periphery is cut out. However, the shape of the glass substrate 10 is not limited to a disc shape and may be any shape, for example, a polygonal plate such as a rectangle. Also, the notch N is not an essential component, and the glass substrate 10 does not need to have a notch N formed therein. Hereinafter, the direction perpendicular to the main surface 10A will be referred to as the Z direction. The Z direction can also be called the thickness direction of the glass substrate 10. Furthermore, within the Z-direction, the direction (orientation) from the main surface 10B toward the main surface 10A is defined as the Z1 direction, and the direction (orientation) from the main surface 10A toward the main surface 10B, that is, the direction opposite to the Z1 direction, is defined as the Z2 direction. In the following, the center position (geometric center position) of the glass substrate 10 when viewed from the Z direction is defined as center P0. The radial direction is defined as the direction of the axis along the Z direction passing through center P0. That is, the direction from a point on the end surface 10C toward center P0 is the radially inward direction, and the direction from center P0 toward a point on the end surface 10C toward center P0 is the radially outward direction.

[0012] (Diameter of glass substrate) The diameter D0 of the glass substrate 10 is preferably 150 mm or more and 900 mm or less, more preferably 150 mm or more and 600 mm or less, and even more preferably 150 mm or more and 450 mm or less. When the diameter D0 is within this range, components such as semiconductor devices can be properly supported. Note that if the glass substrate 10 is circular, the diameter D0 refers to the diameter, but if the glass substrate 10 is not circular, it may refer to the maximum value of the distance between any two points on the outer edge of the glass substrate 10.

[0013] (Thickness of Glass Substrate) The thickness of the glass substrate 10, that is, the length in the Z direction between the main surface 10A and the main surface 10B, is preferably 2 mm or less, more preferably 0.5 mm or more and 1.8 mm or less, and even more preferably 0.6 mm or more and 1.5 mm or less. By setting the thickness within this range, the weight will not be excessive, making handling easy, and sufficient rigidity can be ensured to suppress warping of the glass substrate 10 and the semiconductor device.

[0014] (Composition of Glass Substrate) The composition of the glass substrate 10 is arbitrary. However, in the present embodiment, it is preferably to contain the following compounds in mass% (wt%) based on oxides. By setting the glass substrate 10 to the following composition, the members can be appropriately supported. SiO ２ : 40 wt% or more and 75 wt% or less is preferable, and 50 wt% or more and 75 wt% or less is more preferable. Al ２ O ３ : 0 wt% or more and 20 wt% or less is preferable, and 0 wt% or more and 15 wt% or less is more preferable. B ２ O ３ : 0 wt% or more and 20 wt% or less is preferable, and 0 wt% or more and 10 wt% or less is more preferable. MgO: 0 wt% or more and 25 wt% or less is preferable. CaO: 0 wt% or more and 25 wt% or less is preferable, and 0 wt% or more and 15 wt% or less is more preferable. SrO: 0 wt% or more and 10 wt% or less is preferable. BaO: 0 wt% or more and 20 wt% or less is preferable, and 0 wt% or more and 15 wt% or less is more preferable. Li ２ O: 0 wt% or more and 40 wt% or less is preferable. Na ２ O: 0 wt% or more and 15 wt% or less is preferable. K ２ O: 0 wt% or more and 10 wt% or less is preferable. ZrO ２ : 0 wt% or more and 10 wt% or less is preferable, 0 wt% or more and 8 wt% or less is more preferable, and 0 wt% or more and 5 wt% or less is even more preferable. TiO ２ : 0 wt% or more and 5 wt% or less is preferable. Y ２ O ３ : 0 wt% or more and 10 wt% or less is preferable.

[0015] (Mark) A mark 100, which is an imprint, is formed on the main surface 10A of the glass substrate 10. The mark 100 may be an identifier composed of at least one of the following: numbers, letters, two-dimensional codes, and figures. Each of the numbers, letters, two-dimensional codes, and figures may be one or more. The mark 100 as an identifier can be said to be a mark for identifying the glass substrate 10. The mark 100 as an identifier can be used, for example, for identifying and managing the glass substrate 10.

[0016] Mark 100 is not limited to being an identifier for identifying the glass substrate 10, but may also be, for example, an alignment mark. An alignment mark is, for example, a mark for positioning the glass substrate 10, and can be used for positioning and aligning the glass substrate 10 during processing such as handling, cutting, chamfering, and bonding. The alignment mark may also be a mark for determining the orientation of the glass. That is, when stacking a device on a glass substrate, the mark may be engraved on the opposite side of the surface on which the device is stacked to accommodate variations in warping during device manufacturing. As a result, the orientation of the glass warping can be determined by the alignment mark. By engraving the mark on the opposite side of the surface on which the device is stacked, the identifier of the glass substrate 10 can be recognized even after the device has been stacked. The orientation of the warping is determined by the positive or negative sign of the BOW, but it may also be determined by the amount of deflection on the three-point support. The items to be bonded to the glass may be not only devices, but also thin films of metal or organic material, semiconductor wafers such as Si, glass, etc.

[0017] The mark 100 may be provided at any position on the main surface 10A, but as shown in Figure 1, in this embodiment, it is provided in region AR on the radially outer side of the main surface 10A (i.e., near the end face 10C). If position AR1 is the radially outermost position on the outer circumference of region AR, then, when viewed from the Z direction, the radial distance L1 between position AR1 and the end face 10C is preferably 0.1 mm or more and 12 mm or less, preferably 0.1 mm or more and 10 mm or less, more preferably 0.3 mm or more and 7 mm or less, and even more preferably 0.5 mm or more and 5 mm or less. In other words, it is preferable that the mark 100 be provided on the main surface 10A at a distance of L1 or more radially inward from the end face 10C. Furthermore, if position AR2 is defined as the radially innermost position on the outer circumference of region AR, the radial distance L2 between position AR2 and the end face 10C, as viewed from the Z direction, is preferably 1.1 mm or more and 12 mm or less, more preferably 1.3 mm or more and 9 mm or less, and even more preferably 1.5 mm or more and 7 mm or less. In other words, it is preferable that the mark 100 be provided on the main surface 10A at a position radially inward from the end face 10C at a distance of L2 or less. By providing the mark 100 at such a position, it can function appropriately as an identifier or alignment mark.

[0018] Hereafter, each number, character, and graphic that constitutes mark 100 will be referred to as a mark element 102. That is, mark 100 is composed of multiple mark elements 102. However, mark 100 may also be composed of a single mark element 102.

[0019] Figure 2 is a schematic diagram of an example of a mark. In the example in Figure 2, the mark 100 is shown as an identifier composed of 12 mark elements 102 arranged in a straight line. However, the mark 100 is not limited to this configuration. For example, the mark 100 may be composed of each mark element 102 arranged in a non-linear manner. Alternatively, the mark 100 may be composed of each mark element 102 arranged in two or more rows, either linearly or non-linearly.

[0020] The overall dimensions of the mark 100 are not particularly limited, but for example, in the case of a linear arrangement of mark elements 102 as shown in Figure 2, the spacing between characters M2 is in the range of 1.420 ± 0.025 mm, and the vertical length M3 may be 1.624 ± 0.025 mm. If the mark 100 is composed of a non-linear arrangement of mark elements 102, the spacing between characters M2 and the vertical length M3 of the mark 100 are defined as the length of the first side and the length of the second side of the minimum rectangle that includes the mark 100, respectively. The spacing between characters M2 is the distance between the center of a mark element 102 and the center of a mark element 102 adjacent to that mark element 102 in the horizontal direction, and the vertical length M3 is the vertical distance between the center of the outermost dot 104 of the mark element 102 in the vertical direction and the center of the outermost dot 104 in the vertical direction.

[0021] A mark element 102 (mark 100) is composed of multiple dots 104. In other words, a single mark element 102 or mark 100 is formed by multiple dots 104. In this embodiment, the dots 104 do not overlap but are formed separately. The pitch M1 between adjacent dots 104 is defined by SEMI AUX015-1106 SEMI OCR CHARACTER OUTLINES and SEMI-T7-0303, and is defined by the type of font or two-dimensional code. The pitch M1 refers to the distance between the center of one dot 104 and the center of the dot 104 adjacent to that dot 104, in the direction along the main surface 10A.

[0022] The dot 104 is created by mechanical processing such as laser processing or sandblasting, or by chemical etching, printing, etc. In particular, when manufactured by laser processing, the mark element 102 is composed of multiple laser irradiation marks. The size and pitch of the laser irradiation marks are determined by the configuration of the laser processing machine's optical system.

[0023] (Dots) Figure 3 is a schematic enlarged view of the portion of the glass substrate where dots are formed, and Figure 4 is a cross-sectional view taken along line A-A in Figure 3. Figure 4 can be described as a cross-sectional view of the glass substrate 10 when the plane PL passing through the center of the dot 104 and along the Z direction is used as the cross section. The dot 104 refers to a depression formed on the main surface 10A of the glass substrate 10. However, the shape of the dot does not necessarily have to be a depression, i.e., a concave shape. For example, when formed by printing, it is a convex shape, and when dots are formed by sandblasting or the like, the surface roughness of the corresponding area increases, improving the visibility as a mark. In this embodiment, the dot 104 is formed by irradiating the main surface 10A with laser light. That is, the dot 104 in this embodiment can be described as a laser irradiation mark (irradiation mark of laser light). One dot 104 may be formed by multiple laser irradiation marks or by one laser irradiation mark. The laser may be irradiated multiple times at the same location to make it easier to read the depth of the processed dot, or it may be irradiated while shifting at a constant pitch to form the dot. A single laser irradiation mark refers to an irradiation mark formed by a single shot of laser light. That is, the dot 104 may be formed by laser light irradiated in one cycle from when the laser light is output until it is stopped, or it may be formed by multiple laser irradiation marks. That is, the dot 104 may be formed by laser light irradiated intermittently over multiple cycles.

[0024] (Shape of the dot) As shown in Figure 3, the dot 104 is circular when viewed from the Z direction. However, the shape of the dot 104 when viewed from the Z direction is not limited to a circle. For example, the dot 104 may be elliptical when viewed from the Z direction. Also, by combining multiple laser irradiation marks, it may be a ring, rectangle, double circle, an incomplete circle like the letter "C", or a spiral shape.

[0025] As shown in Figure 4, the dot 104 has a bottom surface 104A and a side surface 104B. The bottom surface 104A refers to the bottom portion of the dot 104, and the side surface 104B refers to the side portion that connects the bottom surface 104A of the dot 104 to the main surface 10A of the glass substrate 10. The side surface 104B includes a side portion 104B1, a connecting portion 104B2, and a connecting portion 104B3. The side portion 104B1 is the portion that forms the side surface of the dot 104. The connecting portion 104B2 is a portion formed at the end of the side portion 104B1 opposite to the Z direction, and has an R shape that connects the bottom surface 104A and the side portion 104B1. The connecting portion 104B3 is a portion formed at the end of the side portion 104B1 on the Z direction side, and has an R shape that connects the side portion 104B1 and the main surface 10A of the glass substrate 10. However, the side surface 104B is not limited to including R-shaped connecting portions 104B2 and 104B3, and the connecting portion between the bottom surface 104A and the side surface 104B1, or the connecting portion between the side surface 104B1 and the main surface 10A of the glass substrate 10, may have an edge shape (angular).

[0026] The diameter D1 of the dot 104 is preferably 50 μm or more and 200 μm or less, more preferably 80 μm or more and 150 μm or less, and even more preferably 90 μm or more and 120 μm or less. By having the diameter of the dot 104 within this range, one dot 104 can be made relatively large, allowing the mark 100 to be properly visible. As shown in Figure 4, the diameter D1 of the dot 104 may refer to the diameter of a virtual circle formed by the intersection of the curved surface along the side portion 104B1 (corresponding to the side surface of a frustocone) and the plane along the main surface 10A. If the dot 104 is not circular, the diameter D1 may be the longest distance between two points on the outer circumference of the virtual region formed by the intersection of the surface along the side portion 104B1 and the plane along the main surface 10A.

[0027] (Depth of the dot) The depth H of the dot 104 is preferably between 0.5 μm and 7.0 μm, more preferably between 0.5 μm and 5.0 μm, and even more preferably between 0.5 μm and 3.0 μm. By having a depth H within this range, cracking of the glass substrate 10 starting from the dot 104 can be suppressed and ease of reading can be ensured. The depth H refers to the distance between the main surface 10A and the bottom surface 104A in the Z direction. The depth H of the dot 104 is measured by the following method. The cross-sectional shape of an arbitrary dot is measured using the laser microscope described above for the dots of the mark. Then, the lowest point of the cross section is taken as S, and the difference in the Z direction between the main surface 10A, which is the main surface of the glass, and the lowest point S is taken as the depth H. However, in the case of a form in which the outer periphery of the dot has a concave shape as shown in Figure 5, the concave part of the outer periphery of the dot does not need to be taken into account as the lowest point. The depth H can be measured using an OLYMPUS OLS4000.

[0028] (Angle of inclination of the side surface of the dot) The diameter of the dot 104 may be constant towards the bottom surface 104A, but as shown in Figure 4, the diameter may decrease towards the bottom surface 104A. In this case, the angle of inclination θ of the side surface 104B of the dot 104 is preferably 5° or more and 56° or less, more preferably 5° or more and 55° or less, and even more preferably 15° or more and 55° or less. When the angle of inclination θ is within this range, even if the depth H of the dot 104 is made shallow as in the above range, light can be reflected appropriately and a decrease in the visibility of the mark 100 can be suppressed. The angle of inclination θ refers to the angle between the bottom surface 104A and the side surface 104B of the dot 104, and can also be said to be the gradient of the dot 104. The angle of inclination θ can also be said to be the angle between the line segment LI that passes over the side surface 104B1 and along the plane PL and the bottom surface 104A. More specifically, the line segment LI can be described as a straight line that passes from position P1 to position P2 on the side surface 104B and lies along the plane PL. Position P1 refers to a position 20% of the depth H away from the bottom surface 104A in the Z direction, and position P2 refers to a position on the side surface 104B 80% of the depth H away from the bottom surface 104A in the Z direction. In the example in Figure 4, position P1 is the boundary between the side surface 104B1 and the connecting part 104B2, and position P2 is the boundary between the side surface 104B1 and the connecting part 104B3.

[0029] (Shape of the glass substrate) Next, the shape of the glass substrate 10 according to this embodiment will be described in more detail.

[0030] (Chamfering) Figure 5 is a schematic cross-sectional view of the glass substrate according to this embodiment. The outer edge of the glass substrate 10 according to this embodiment is chamfered. That is, as shown in Figure 5, the end face 10C of the glass substrate 10 includes an end face portion 10C1 and a chamfered portion 10C2. The end face portion 10C1 corresponds to the unchamfered part of the end face 10C, or in other words, it is the radially outermost part of the end face 10C. The chamfered portion 10C2 is a chamfered surface that connects the end face portion 10C1 and the main surface 10A (main surface 10B). The chamfered portion 10C2 is flat (i.e., C-chamfered) when viewed from a direction perpendicular to the Z direction, that is, in a cross-sectional view as shown in Figure 5, but is not limited to that and may be curved (i.e., R-chamfered). The end face 10C has a shape that includes the end face portion 10C1 and the chamfered portion 10C2 as shown in Figure 5, over the entire circumferential area of ​​the glass substrate 10. Furthermore, in this embodiment, the chamfered portion 10C2 is formed on both the Z1 direction side and the Z2 direction side. That is, the chamfered portion 10C2 on the Z1 direction side connects the main surface 10A and the end surface portion 10C1, and the chamfered portion 10C2 on the Z2 direction side connects the main surface 10B and the end surface portion 10C1. However, it is not limited to this, and the chamfered portion 10C2 may be provided on only one side of the Z1 direction side and the Z2 direction side (for example, only on the Z1 direction side).

[0031] The glass substrate 10 does not necessarily have to be chamfered, and in this case, the end face 10C may include the end face portion 10C1 and not include the chamfered portion 10C2.

[0032] (Thickness reduction near the end face) Here, the boundary position between the main surface 10A and the end face 10C of the glass substrate 10 is defined as the first position PA. In this embodiment, since a chamfered portion 10C2 is formed, the first position PA (boundary position) refers to the boundary position between the main surface 10A and the chamfered portion 10C2. If the chamfered portion 10C2 is not formed, the first position PA (boundary position) will refer to the boundary position between the main surface 10A and the end face portion 10C1. Furthermore, the position on the main surface 10A that is 1 mm radially inward from the first position PA (boundary position) is defined as the second position PB. That is, as shown in Figure 1, the second position PB is a position 1 mm toward the center P0 from the first position PA on the straight line PL connecting the first position PA and the center P0, when viewed from the Z direction. Note that the first position PA and the second position PB are located within the area on the main surface 10A where no marks 100 (dots 104) are formed.

[0033] In this embodiment, the second position PB is located on the Z1 side of the first position PA. More specifically, it is preferable that the main surface 10A of the glass substrate 10 is inclined in the Z1 direction as it moves radially inward (along the straight line PL) from the first position PA to the second position PB. In other words, the glass substrate 10 has a shape in which the thickness (plate thickness) gradually decreases in the region inside the chamfered portion 10C2 as it moves from the second position PB to the first position PA (radially outward).

[0034] Here, the distance in the Z direction between the first position PA and the second position PB is defined as the plate thickness reduction amount D. In this case, the plate thickness reduction amount D is between 0.102 μm and 2.01 μm, preferably between 0.102 μm and 1 μm, and more preferably between 0.102 μm and 0.5 μm. The plate thickness reduction amount D can be measured as follows: Using a laser microscope (for example, an Olympus OLS4000), the height a (height in the Z direction) of the main surface 10A at the first position PA and the height b (height in the Z direction) of the main surface 10A at the second position PB are measured under the condition of an objective lens magnification of 10x. Then, the absolute value of the difference between height a and height b (|a - b|) is calculated as the plate thickness reduction amount D.

[0035] By setting the lower limit of the plate thickness reduction amount D within this range, it is possible to suppress the occurrence of minute scratches in the region near the end face 10C of the main surface 10A, thereby suppressing cracking of the glass substrate 10. In particular, when a mark 100 is formed in region AR near the end face 10C, if there are minute scratches near that region AR, the formation of the mark 100 may cause the scratches to propagate, potentially leading to cracking of the glass substrate 10. In contrast, according to this embodiment, minute scratches can be suppressed, thus suppressing cracking even when the mark 100 is formed. Furthermore, by setting the plate thickness reduction amount D as in this embodiment, it is thought that, for example, when polishing the main surface 10A, strong contact of abrasive grains with the region near the end face 10C can be suppressed, thereby suppressing minute scratches. In addition, by setting the upper limit of the plate thickness reduction amount D within this range, the mark 100 can be appropriately formed on the main surface 10A, and a decrease in the visibility of the mark 100 can be suppressed. For example, the mark 100 is formed to a predetermined depth, using the central region of the glass substrate 10, where the thickness reduction is small, as the reference plane. In this case, if the thickness reduction amount D is too large, the mark 100 (dot 104) will become shallower than expected in the region near the edge face 10C by the amount of the thickness reduction amount D, resulting in reduced visibility. In contrast, by setting the upper limit of the thickness reduction amount D to the above range, the mark 100 (dot 104) will not become too shallow, and the reduction in visibility can be suppressed.

[0036] The method for setting the plate thickness reduction amount D within the above range is arbitrary; for example, the plate thickness reduction amount D can be set within the above range by appropriately adjusting the manufacturing conditions of the glass substrate 10. Examples of manufacturing conditions in this case include the glass plate formation conditions and polishing conditions.

[0037] Furthermore, the ratio of the plate thickness reduction amount D to the depth H of the dot 104 (D / H) is preferably 1% to 90%, more preferably 5% to 80%, and even more preferably 10% to 60%. This allows the plate thickness reduction amount D to be set to an appropriate size relative to the depth of the dot 104, thereby more effectively suppressing cracking and the reduction in visibility of the mark 100.

[0038] (Amount of reduction in plate thickness in the central region) The main surface 10A of the glass substrate 10 preferably has a smaller inclination amount in the Z1 direction (the inclination in the Z direction of the straight line connecting the second position PB to the center P0) from the second position PB to the center P0 in the radially inward direction than the inclination amount in the Z1 direction (the inclination in the Z direction of the straight line connecting the first position PA to the second position PB) from the first position PA to the second position PB in the radially inward direction. More specifically, the main surface 10A of the glass substrate 10 is preferably flat from the second position PB to the center P0, or in other words, preferably does not incline in the Z direction.

[0039] Here, the distance in the Z direction between the second position PB and the center P0 is defined as the amount of reduction in plate thickness Da. In this case, the amount of reduction in plate thickness Da is preferably smaller than the amount of reduction in plate thickness D. The amount of reduction in plate thickness Da is preferably 0 μm or more and 1 μm or less, more preferably 0 μm or more and 0.5 μm or less, and still more preferably 0 μm or more and 0.1 μm or less. The amount of reduction in plate thickness Da can be measured in the same manner as the amount of reduction in plate thickness D.

[0040] The glass substrate 10 can maintain flatness and function properly as a substrate by having a smaller reduction in plate thickness in the radially inner side than the second position PB.

[0041] (Microscopic scratches) The average length of the microscopic scratches in the vicinity of the first position PA on the main surface 10A of the glass substrate 10 is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 30 μm or less. The average width of the microscopic scratches in the vicinity of the first position PA on the main surface 10A of the glass substrate 10 is preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 3 μm or less. The average depth of the microscopic scratches in the vicinity of the first position PA on the main surface 10A of the glass substrate 10 is preferably 1 μm or less, more preferably 0.5 μm or less, and still more preferably 0.3 μm or less. By having such small sizes of the microscopic scratches, cracking of the glass substrate 10 can be appropriately suppressed. Note that making the sizes of such microscopic scratches this small can be achieved, for example, by setting the amount of reduction in plate thickness D within the above range.

[0042] The size of the micro damage can be measured as follows. First, the glass substrate 10 is immersed in an etching solution (Stella Chemifa's 1 wt% high - purity hydrofluoric acid for semiconductors) at 24.0 °C for 5 minutes. Of the main surface 10A of the glass substrate 10 after being immersed in the etching solution, the entire circumferential region from the boundary position between the main surface 10A and the end face 10C to a position 1 mm radially inward from the boundary position is observed with a laser microscope (for example, OLS4000 manufactured by Olympus) under the condition of a magnification of 20 times of the objective lens to obtain an observation image. The observation image is processed by binarization, and the region on the side with lower luminance is detected as a damage. Three regions are picked up as representative damages in descending order of the numerical value of the area of the detected damage. Then, the region of the representative damage on the main surface 10A is observed with a laser microscope (for example, OLS4000 manufactured by Olympus) under the condition of a magnification of 20 times of the objective lens, and the length, width, and depth of the representative damage are measured. The average value of the lengths of the three representative damages is calculated as the average length of the micro damage, the average value of the widths of the three representative damages is calculated as the average width of the micro damage, and the average value of the depths of the three representative damages is calculated as the average depth of the micro damage.

[0043] (Manufacturing method of glass substrate) The glass substrate 10 in the present embodiment may be manufactured by any method. An example of the manufacturing method will be described below. FIG. 6 is a flowchart showing the manufacturing method of the glass substrate according to the present embodiment.

[0044] As shown in FIG. 6, in this manufacturing method, first, a glass plate is formed (step S10). In step S10, a glass raw material is made into a glass state by any glass melting and forming method such as float, fusion, ingot molding, etc., and the glass is manufactured and processed into the shape of the glass substrate to obtain a glass plate. In the example of the present embodiment, since the glass substrate 10 is disk - shaped, the glass is cut out into a circular shape by any means such as slicing, circular cutting, etc. to form a glass plate. Note that a notch N may be formed in the formed glass plate.

[0045] Next, the glass plate is chamfered (step S12) to form the chamfered portion 10C2. If the chamfered portion 10C2 is not to be provided, this step is unnecessary. The glass plate may also be washed after step S12 or the subsequent step S14.

[0046] Next, the glass plate is polished (step S14). In this step, one main surface of the glass plate (the main surface that will become main surface 10A) and the other main surface (the main surface that will become main surface 10B) are polished. However, only one main surface may be polished. The chamfered portion 10C2 may also be polished. The polishing method here is arbitrary, but for example, lapping may be performed.

[0047] Next, marks 100 are formed on the main surface 10A of the glass plate to obtain the glass substrate 10 (step S16). The method of forming the marks 100 is arbitrary, but the marks 100 may be formed by irradiating the main surface 10A with laser light.

[0048] (Effects) The glass substrate 10 according to the first aspect of this disclosure has a main surface 10A (first main surface) and a main surface 10B (second main surface), a mark 100 is formed on the main surface 10A, the boundary position between the main surface 10A and the end surface 10C is defined as the first position PA, and the position on the main surface 10A 1 mm radially inward from the first position PA is defined as the second position PB. The second position PB is located on the Z1 direction (first direction), which is the direction from the main surface 10B toward the main surface 10A, side of the first position PA, and the distance between the first position PA and the second position PB in the Z direction (thickness direction) (plate thickness reduction amount D) is 0.102 μm or more and 2.01 μm or less. According to this disclosure, by having the plate thickness reduction amount D within the above range, it is possible to suppress cracking and suppress the reduction in visibility of the mark 100 at the same time.

[0049] The glass substrate 10 according to the second aspect of this disclosure is the same as the glass substrate 10 according to the first aspect, wherein the mark 100 is formed on the main surface 10A at a position (region AR) that is 0.01 mm to 12 mm radially inward from the end surface 10C. According to this disclosure, the formation of the mark 100 can suppress cracking of the glass substrate 10.

[0050] A glass substrate 10 according to a third aspect of this disclosure is a glass substrate 10 according to the first or second aspect, wherein the mark 100 is composed of a plurality of dots 104. According to this disclosure, the formation of the dots 104 can suppress cracking of the glass substrate 10.

[0051] The glass substrate 10 according to the fourth aspect of this disclosure is the glass substrate 10 according to the third aspect, wherein the dot 104 is a depression formed on the main surface 10A. According to this disclosure, the formation of the dot 104 can suppress cracking of the glass substrate 10.

[0052] The glass substrate 10 according to the fifth aspect of this disclosure is the glass substrate 10 according to the fourth aspect, wherein, when viewed from the Z direction, the dots 104 are circular in shape with a diameter of 50 μm or more and 200 μm or less. According to this disclosure, the formation of the dots 104 can suppress cracking of the glass substrate 10.

[0053] The glass substrate 10 according to the sixth aspect of this disclosure is the glass substrate 10 according to the fourth or fifth aspect, wherein the depth of the dots 104 is 0.5 μm or more and 5.0 μm or less. According to this disclosure, the formation of the dots 104 can suppress cracking of the glass substrate 10.

[0054] The glass substrate 10 according to the seventh aspect of this disclosure is a glass substrate 10 according to any of the first to sixth aspects, and is circular or rectangular in shape. According to this disclosure, it is possible to achieve both suppression of cracking and suppression of the reduction in visibility of the mark 100.

[0055] The glass substrate 10 according to the eighth aspect of this disclosure is a glass substrate 10 according to any of the first to seventh aspects, and is used as a glass substrate for supporting a semiconductor device. According to this disclosure, it is possible to achieve both suppression of cracking and suppression of the reduction in visibility of the mark 100.

[0056] (Examples) Next, examples will be described. Table 1 shows each example.

[0057]

[0058] (Example 1) In Example 1, a wafer-shaped glass plate with a diameter of 300 mm and a thickness of 0.7 mm was prepared, both main surfaces were polished, and a YAG laser (wavelength 532 mm, multiple irradiations) was irradiated at a position 1.05 mm radially inward from the end surface 10C on the main surface 10A to form a mark and obtain a glass substrate. The thickness reduction amount D of the obtained glass substrate was measured under the conditions described in this embodiment. The thickness reduction D at the first position PA and second position PB in the marked area (near where the mark 100 is formed), the thickness reduction D at the first position PA and second position PB at position A (90° circumferentially from the center P0 where the mark 100 is formed), the thickness reduction D at the first position PA and second position PB at position B (180° circumferentially from the center P0 where the mark 100 is formed), and the thickness reduction D at the first position PA and second position PB at position C (270° circumferentially from the center P0 where the mark 100 is formed) were measured. In addition, the average length, average width, and average depth of the micro-scratches on the obtained glass were measured under the conditions described in this embodiment. The depth of the marks (depth of the dots) was also measured. The measurement results for the thickness reduction D, the size of the micro-scratches, and the depth of the marks at each position are shown in Table 1.

[0059] (Examples 2 to 10) In Examples 2 to 10, glass substrates were obtained by forming marks in the same positions as in Example 1 on a glass plate of the same shape as in Example 1. Table 1 shows the measurement results of the plate thickness reduction D and the size of minute scratches at each position.

[0060] (Evaluation) For each example of glass substrate, the visibility of cracks and marks was evaluated. In the crack evaluation, the presence or absence of cracks near the marks was visually confirmed. In the mark visibility evaluation, light was shone on the main surface 10A, and a circle (○) was used if the marks were clearly visible, and a cross (×) was used if the marks were difficult to see.

[0061] As shown in Table 1, in Examples 1 to 8, where the plate thickness reduction D is between 0.102 μm and 2.01 μm, no cracks were observed and the marks were clearly visible, indicating that both crack suppression and suppression of the decrease in visibility of the marks 100 can be achieved. On the other hand, in Example 9, where the plate thickness reduction D is small, cracks were observed, indicating that crack suppression could not be achieved. On the other hand, in Example 10, where the plate thickness reduction D is large, the marks were not clearly visible.

[0062] Although embodiments of the present invention have been described above, the embodiments are not limited to those described herein. Furthermore, the aforementioned components include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the aforementioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above.

[0063] 10 Glass substrate 10A Main surface 10C Edge surface 100 Mark D Thickness reduction PA First position PB Second position

Claims

1. A glass substrate having a first main surface and a second main surface, wherein a mark is formed on the first main surface, and the boundary position between the first main surface and the end surface is defined as the first position, and a position on the first main surface 1 mm radially inward from the first position is defined as the second position, wherein the second position is located on the first direction side, which is the direction from the second main surface toward the first main surface, than the first position, and the distance between the first position and the second position in the thickness direction of the glass substrate is 0.102 μm or more and 2.01 μm or less.

2. The glass substrate according to claim 1, wherein the mark is formed on the first main surface at a position 0.1 mm to 12 mm away from the end face in the radial direction.

3. The glass substrate according to claim 1, wherein the mark is composed of a plurality of dots.

4. The glass substrate according to claim 3, wherein the dot is a depression formed on the first main surface.

5. The glass substrate according to claim 4, wherein, when viewed from the thickness direction, the dots are circular in shape with a diameter of 50 μm or more and 200 μm or less.

6. The glass substrate according to claim 4, wherein the depth of the dots is 0.5 μm or more and 5.0 μm or less.

7. A glass substrate according to any one of claims 1 to 6, which is circular or rectangular in shape.

8. A glass substrate according to any one of claims 1 to 6, used as a glass substrate for supporting a semiconductor device.

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