JP7260984B2 - Substrate holding member - Google Patents

Description

The present invention relates to a substrate holding member used for holding a substrate such as a semiconductor wafer by vacuum suction.

A substrate comprising a plurality of upward projections projecting upward from the upper surface of a flat substrate, grooves recessed from the lower surface of the substrate, and vent holes communicating with the grooves and having openings on the upper surface of the substrate. Retaining members are known. The substrate is supported by at least a portion of the plurality of upward protrusions, and the lower surface side of the substrate is placed on the stage. A negative pressure region is formed in the gap sandwiched between the substrates, and an attractive force (vacuum adsorption force) directed toward the substrate acts on the substrate. In this case, the substrate, and thus the substrate, may locally dent downward in the thin region above the groove. In order to suppress this dent, it has been proposed to form a downwardly protruding portion in the groove. (See, for example, Patent Document 1).

JP 2017-212343 A

However, there are cases where the base is locally recessed downward at portions of the thin region of the base that are not provided with the downward protrusion or at portions where the downward protrusion is not provided. When a hollow space is provided inside the base instead of the groove, it is difficult to provide a structure for supporting the thin region above the hollow space from below, and the base is locally dented. Sometimes.

Therefore, the present invention improves the overall flatness of the substrate by suppressing the local reduction in flatness of the substrate immediately above the thin region when the substrate has a local thin region for forming a negative pressure. It is an object of the present invention to provide a substrate holding member that can be improved.

A substrate holding member according to a first aspect of the present invention comprises a flat substrate having an upper surface and a lower surface, a plurality of upper surface projections projecting upward from the upper surface of the substrate, and recesses recessed from the lower surface of the substrate. and one or more ventilation holes communicating with the ventilation path and having openings in the upper surface of the substrate , wherein the ventilation is performed in the substrate It has a ridge projecting downward from the ceiling above the passage, and the lower end of the ridge is positioned at the same height as the lower surface or the lower end of the base , and the ridge is the air passage. One or more ridges extend linearly in the linear recesses forming It is characterized by

According to the substrate holding member of the first aspect of the present invention, the air passage is vacuum-sucked in a state in which the substrate is supported on the base on the lower surface side and the substrate such as a wafer is placed on the upper surface side. . As a result, a negative pressure region is formed in a space vertically sandwiched by the upper and lower surfaces of the substrate through the air hole communicating with the air passage, and a suction force directed toward the substrate acts on the substrate.

The substrate holding member further includes a ridge extending in a specified direction parallel to the upper surface of the base and protruding downward from the ceiling above the air passage in the base. The lower end of the ridge is positioned at the same height as the lower surface or lower end of the base. For this reason, the ridge functions as a reinforcing structure that supports the ceiling from below by the table on which the base is placed. Further, by extending the ridges in the specified direction parallel to the upper surface of the base, the mechanical strength of the ceiling portion is improved at least in the specified direction.

As a result, due to the formation of a negative pressure area in the ventilation path, when a suction force acts downward on the ceiling of the base body, the recess of the ceiling and eventually the ceiling (more precisely, the area overlapping the ceiling in the vertical direction) ) is suppressed or prevented from downwardly displacing the upper surface protrusions arranged in the . Therefore, the substrate can be uniformly brought into contact with the upper end surfaces of all the upper surface protrusions including the upper surface protrusions disposed above the ventilation path, and the substrate can be held by suction while being held by the substrate holding member. Improvement in flatness is achieved.

A substrate holding member according to a second aspect of the present invention comprises a plate-like substrate having an upper surface and a lower surface, a plurality of upper surface projections projecting upward from the upper surface of the substrate, and between the upper surface and the lower surface of the substrate. an air passage constituted by a hollow space at least partially defined by a ceiling surface of the base body located thereon and a floor surface of the base body facing the ceiling surface; one or more air holes having openings in the upper surface of the substrate holding member, the ceiling portion above the air passages in the base extending in a designated direction parallel to the upper surface of the base and the lower end of the ridge abuts or is integrated with the floor surface, or extends in the specified direction, below the air passage in the base In a straight concave portion having a ridge projecting upward from the floor at the bottom, the upper end of the ridge abuts the ceiling surface, and the ridge constitutes the air passage, One or more ridges extend in a straight line, and the one or more ridges extend in an arc shape in the arcuate recess forming the air passage.

According to the substrate holding member of the second aspect of the present invention, the air passage is vacuum-sucked in a state in which the base body is supported on the base on the bottom side thereof and the substrate such as a wafer is placed on the top side thereof. . As a result, a negative pressure region is formed in a space vertically sandwiched by the upper and lower surfaces of the substrate through the air hole communicating with the air passage, and a suction force directed toward the substrate acts on the substrate.

The substrate holding member further includes a ridge extending in a specified direction parallel to the upper surface of the base and protruding downward from the ceiling above the air passage in the base, and the lower end of the ridge extends from the base. It is in contact with or integrated with the floor of the ventilation path. Alternatively, the substrate holding member further includes a ridge extending in a specified direction and protruding upward from the floor below the ventilation path in the base body, and the upper end of the ridge is in contact with the ceiling surface. abutting. Therefore, the ridge functions as a reinforcing structure that supports the ceiling from below with the floor. Further, by extending the ridges in the specified direction parallel to the upper surface of the base, the mechanical strength of the ceiling portion is improved at least in the specified direction.

As a result, due to the formation of a negative pressure area in the ventilation path, when a suction force acts downward on the ceiling of the base, the ceiling is recessed, and thus the upper surface protrusion arranged on the ceiling is displaced downward. is suppressed or prevented. Therefore, the substrate can be uniformly brought into contact with the upper end surfaces of all the upper surface protrusions including the upper surface protrusions disposed above the ventilation path, and the substrate can be held by suction while being held by the substrate holding member. Improvement in flatness is achieved.

In each of the substrate holding members according to the first and second aspects of the present invention, on the upper surface of the base, at least part of the upper surface of the upper surface protrusions arranged on the ceiling portion is located in the area where the protrusions exist. It is preferable that a convex portion is arranged.

According to the substrate holding member having this configuration, at least a portion of the upper surface convex portion arranged in the ceiling portion on the upper surface of the base is supported from below by the convex strip that is relatively unlikely to be depressed downward. are arranged. Therefore, on the upper surface of the base, at least some of the upper surface protrusions arranged on the ceiling portion are displaced downward relative to the other upper surface protrusions arranged outside the ceiling portion. situation is avoided. Therefore, the substrate can be brought into uniform contact with at least a portion of the upper surface projections arranged on the ceiling portion and the upper end surface of the upper surface projections arranged away from the ceiling portion, thereby making the substrate holding member. This improves the flatness of the substrate when it is held by suction.

1 is a top view of a substrate holding member as a first embodiment of the present invention; FIG. FIG. 2 is a longitudinal sectional view of the substrate holding member taken along line II-II in FIG. 1; Explanatory drawing about the 1st extension mode in the XZ plane of a ridge. FIG. 11 is an explanatory diagram regarding a second extension mode of the ridge on the XZ plane; FIG. 11 is an explanatory diagram relating to a third extension mode of the ridge on the XZ plane; FIG. 11 is an explanatory diagram relating to a fourth extension mode of the ridge on the XZ plane; Explanatory drawing regarding the first extension mode of the air passage and the ridge on the XY plane. FIG. 11 is an explanatory diagram regarding a second extension mode of the air passage and the ridge on the XY plane; FIG. 11 is an explanatory diagram relating to a third extension mode of the air passage and the ridge on the XY plane; FIG. 11 is an explanatory diagram relating to a fourth extension mode of the air passage and the ridge on the XY plane; FIG. 10 is an explanatory diagram relating to a first extension mode of the air passage and the ridge on the YZ plane; FIG. 10 is an explanatory diagram relating to a second extension mode of the air passage and the ridge on the YZ plane; FIG. 11 is an explanatory diagram regarding a third extension mode of the air passage and the ridge on the YZ plane; FIG. 11 is an explanatory diagram relating to a fourth extension mode of the air passage and the ridge on the YZ plane; FIG. 3 is a longitudinal sectional view corresponding to FIG. 2 of a substrate holding member as a second embodiment of the present invention;

(First embodiment)
(composition)

A substrate holding member as a first embodiment of the present invention shown in FIGS. An annular upper surface protrusion 114 that protrudes upward from the upper surface 101 of the substrate 1 and extends annularly so as to surround the plurality of upper surface protrusions 110, and a plurality of lower surface protrusions that protrude downward from the lower surface 102 of the base 1. a portion 120, an air passage 22 formed by a recess recessed from the lower surface 102 of the base 1, a ventilation hole 21 communicating with the air passage 22 and having an opening in the upper surface 101 of the base 1, and the base 1 , a ridge 121 protruding downward from a ceiling portion 221 above the air passage 22, and an air passage protruding downward from the lower surface 102 of the base 1 and airtightly sealing when the air passage 22 is sucked. An inner annular lower surface projection 122 extending annularly so as to surround the lower surface opening of 22 , and an annular lower surface projection 122 protruding downward from the outer edge of the lower surface 102 of the base body 1 and surrounding the plurality of lower surface projections 120 . and an extending outer annular undersurface projection 124 .

A base coordinate system (X, Y, Z) fixed with respect to the base 1 is appropriately used to describe the arrangement of each component. The XY plane of the substrate coordinate system is defined to be parallel to each of the upper surface 101 and the lower surface 102 of the substrate 1 . The Z-axis of the base coordinate system is defined to be parallel to the thickness direction of the base 1 .

The substrate 1 has a substantially circular shape when viewed along the Z-axis, for example, and is made of a ceramic sintered body such as SiC, AlN, or Al ₂ O ₃ in a substantially flat plate shape. The plurality of upper surface protrusions 110, the annular upper surface protrusions 114, the plurality of lower surface protrusions 120, the inner annular lower surface protrusions 122, the outer annular lower surface protrusions 124, the air holes 21, and the air passages 22 are each ground or blasted. , milling or laser processing, or a combination thereof. Each of the upper surface 101 and the lower surface 102 of the substrate 1 is formed substantially flat.

The plurality of upper surface protrusions 110 are arranged on the upper surface 101 of the substrate 1 in a grid such as a triangular lattice or a square lattice, and are arranged along each of a plurality of concentric circles, or a plurality of radial lines extending from the center. may be regularly arranged, such as regularly arranged along each of the , or may be irregularly arranged. Arrangement mode or regularity of the upper surface protrusions 110 constituting one group among the plurality of upper surface protrusions 110 (for example, the plurality of upper surface protrusions 110 arranged on the ceiling portion 221 above the ventilation path 22); The arrangement mode or regularity of the upper surface protrusions 110 constituting another group different from the one group (for example, a plurality of upper surface protrusions 110 arranged at a position away from the ceiling part 221) is different. good too.

Each of the plurality of upper surface protrusions 110 has a substantially columnar shape, a substantially frustum shape, a columnar body, a columnar body, a substantially frustum-shaped body, a columnar body or a frustum-shaped body having a small-area bottom surface or lower base on the end face or upper base, a hemisphere, a semi-elliptical sphere, or a It may be formed in various shapes such as a substantially columnar shape with a plurality of steps on which a frustum-shaped body is mounted. An upper end surface 1100 of the upper surface convex portion 110 is formed in a planar shape substantially parallel to the upper surface 101 of the base 1 . The projection amounts of the plurality of upper surface protrusions 110 with respect to the upper surface 101 of the base 1 are the same.

Among the plurality of upper surface protrusions 110 arranged on the ceiling portion 221 above the air passage 22 in the base body 1 , for example, some of the upper surface protrusions 110 , preferably all of the upper surface protrusions 110 are the protrusions 121 . Located in the presence area.

In the vertical cross-sectional view of the substrate holding member, the shape of the annular upper projection 114 is substantially rectangular, substantially trapezoidal, semi-elliptical, semi-circular, or rectangular and semi-circular with a diameter equal to one side of the rectangle. Various shapes, such as combined shapes, are also possible. Note that the annular upper surface protrusion 14 may be omitted. The height position (protrusion amount from the upper surface 101) of the upper end surface 1140 of the annular upper surface protrusion 114 with respect to the upper surface 101 of the base body 1 is lower than or equal to the height position of the upper end surface 1100 of the upper surface protrusion 110. Designed.

The plurality of lower surface convex portions 120 are arranged in a lattice such as a triangular lattice or a square lattice on the lower surface 102 of the base 1, and are arranged along each of a plurality of concentric circles, or a plurality of radial lines extending from the center. may be regularly arranged, such as regularly arranged along each of the , or may be irregularly arranged. Each of the lower surface protrusions 120 may be formed in various shapes similarly to the upper surface protrusions 110 . A lower end surface 1200 of the lower surface convex portion 120 is formed in a planar shape substantially parallel to the lower surface 102 of the base 1 .

The height position (protrusion amount) of the lower end surface 1200 of the lower surface protrusion 120 with respect to the lower surface 102 of the base body 1 is the protrusion amount of the upper surface protrusion 110 with respect to the upper surface 101 of the base body 1 and the projection amount of the annular upper surface protrusion 14 with respect to the upper surface 101 of the base body 1. It may be the same as at least part of the amount of protrusion, may be smaller than all of these, or may be larger than all of these. The height position (protrusion amount) of the lower end surface 1220 of the inner annular lower surface convex portion 122 and the lower end surface 1240 (protrusion amount) of the outer annular lower surface convex portion 124 relative to the lower surface 102 of the base body 1 each correspond to the lower surface of the base body 1. It may be the same as the projection amount of the lower surface convex portion 120 with respect to 102 or may be smaller than the projection amount of the lower surface convex portion 120 . All of the plurality of lower surface protrusions 120 may be omitted. At least one of the inner annular lower surface protrusion 122 and the outer annular lower surface protrusion 124 may be omitted.

The air passage 22 includes, for example, a linear concave portion extending in the radial direction (X direction) in a region off the center of the base 1, which is recessed in the thickness direction of the base 1 from the lower surface 102 of the base 1, and the linear concave portion. and an arcuate recess continuously extending in the circumferential direction (the direction in which θ=arctan (Y/X) changes under the condition that X ² +Y ² is constant) from the inner end of the recess. (See Figure 1). The shape of a longitudinal section (eg, YZ plane) perpendicular to the extending direction (eg, X direction) of each of the linear recess and the arc-shaped recess is substantially rectangular. The vertical cross-sectional shape of the ventilation path 22 perpendicular to the extending direction of the ventilation path 22 may be various shapes such as a trapezoid, a parallelogram, or a semi-elliptical shape with a minor axis or a major axis extending downward. The extending manner of the concave portion that constitutes the air passage 22 may be changed in various ways.
Further, the air passage 22 may branch from a linear recess into a plurality of arc-shaped recesses, or may be a ring-shaped recess extending in the circumferential direction of the base 1, and the ring-shaped recess is connected to the linear recess. may have been

The number of air passages 22 in the base 1 may be singular or plural, and when viewed along the Z-axis, the plurality of air passages 22 are arranged at the center of the base 1, or The arrangement may be arbitrarily changed in design, such as being arranged so as to have rotational symmetry with reference to .

The ratio of the thickness of the ceiling portion 221 (thin portion) above the air passage 22 in the base 1 to the thickness of the base 1 is, for example, within the range of 0.20 to 0.70. For example, when the thickness of the base 1 is 1 mm, the thickness of the ceiling portion 221 is within the range of 0.20 mm to 0.70 mm.

The vent hole 21 is formed of a substantially cylindrical hole penetrating through the base body 1 from the upper surface 101 of the base body 1 to the air passage 22 . The number of air holes 21 communicating with one air passage 22 may be singular or plural, and the number and arrangement of the air holes 21 in the upper surface 101 of the base 1 may be arbitrarily changed in design. . For example, a plurality of (for example, six) vent holes 21 may be arranged so as to have rotational symmetry (for example, six-fold symmetry) about the center of the substrate 1 when viewed along the Z-axis (see FIG. 1). ), the plurality of vents 21 may be arranged asymmetrically.

The ridge 121 extends in the extending direction (designated direction) of the ventilation path 22 . For example, one or a plurality of ridges 121 extend linearly in the linear concave portion forming the air passage 22 . One or a plurality of ridges 121 extend in an arc shape in the arc-shaped concave portion forming the air passage 22 . The lower end portion 1210 of the ridge 121 is at the same height as the lower end portion of the base body 1, that is, the lower end surface 1200 of the lower convex portion 120, the lower end surface 1220 of the inner annular lower convex portion 122, and the lower end surface 1240 of the outer annular lower convex portion 124. (same Z coordinate value). When the lower convex portion 120, the inner annular lower convex portion 122, and the outer annular lower convex portion 124 are omitted, the lower end portion 1210 of the ridge 121 is positioned at the same height as the lower surface 102 of the base body 1. .

For example, the ridge 121 has a width in an extending direction (for example, the X direction) parallel to the upper surface 101 and the lower surface 102 of the base 1, and a width in the extending direction parallel to the upper surface 101 and the lower surface 102 of the base 1. It is formed in a columnar shape, such as a rectangular columnar shape or an arc columnar shape, having a width greater than the width in a direction (for example, the Y direction) perpendicular to the vertical axis (see FIGS. 1 and 2). The aspect ratio of the end face of the column (=the width of the ridge 121 in the extending direction parallel to the upper surface 101 and the lower surface 102 of the substrate 1/the extending direction parallel to the upper surface 101 and the lower surface 102 of the substrate 1 The width of the ridge 121 in the direction perpendicular to ) is, for example, 1.5 or more, preferably 2.0 or more, and more preferably 3.0 or more.

A plane (eg, XZ plane) extending in a specified direction (eg, X direction) parallel to the upper surface 101 and the lower surface 102 of the substrate 1 and a thickness direction (Z direction) of the substrate 1, or the substrate 1 parallel to the curved surface. The shape of the ridges 121 extending in the specified direction in the cross section of can be changed in various ways other than a substantially rectangular shape with the specified direction as the long side direction. For example, the shape may be an approximately trapezoidal or isosceles trapezoidal shape with the upper base below the lower base (see FIG. 3A), a comb shape with teeth directed downward (−Z direction), or the letter "E". A shape that looks like it is rotated clockwise by 90° (see FIG. 3B), and a shape that looks like two trapezoids of different sizes are stacked one on top of the other with a step (see FIG. 3C). (see FIG. 3D), or it may be a shape in which rectangles of different sizes are stacked one on top of the other with steps or a shape like the letter "T" (see FIG. 3D).

The shape of the ridges 121 extending in a specified direction (for example, the X direction) in the cross section of the substrate 1 parallel to a plane (XY plane) parallel to the upper surface 101 and the lower surface 102 of the substrate 1 is such that the specified direction is the long side. It may be changed in various ways other than the substantially rectangular shape as the direction. For example, the shape may be a substantially elliptical shape, a wave shape, a zigzag shape, a triangular shape, a parallelogram shape, or a trapezoidal shape with the designated direction as the major axis direction. The plurality of ridges 121 may extend parallel to the extending direction of the ventilation path 22 (see FIG. 4A), and the plurality of ridges 121 may extend parallel to the extending direction of the ventilation path 22. In addition, it may extend in a direction perpendicular to the extending direction (see FIG. 4B), and the plurality of ridges 121 may be inclined with respect to the extending direction of the air passage 22 and (see FIG. 4C), or the plurality of ridges 121 are inclined with respect to the extending direction of the air passage 22 and extend non-parallel to each other. (see FIG. 4D).

The shape of the ridges 121 extending in the specified direction in the cross section of the substrate 1 parallel to the plane (eg the YZ plane) perpendicular to the specified direction (eg the X direction) can be varied in addition to the substantially rectangular shape. may be The shape is, for example, a trapezoidal or isosceles trapezoidal shape (see FIG. 5A), a stepped trapezoidal shape (see FIG. 5B), a complex shape of a rectangle and a semi-ellipse with the major axis being the lower side (see FIG. 5C), or , a stepped rectangular shape (see FIG. 5D).

The ratio S ₁₂₁ /S ₂₂ of the area S 121 occupied by the ridge 121 in the groove to the area S ₂₂ occupied by the groove (substantially rectangular region with the lower end of the lower surface 102 of _the base 1) constituting the air passage 22 in the cross section. is, for example, 0.50 or less, preferably 0.40 or less, in order to ensure air permeability to the extent that it is possible to avoid a significant shift in the timing of the development of the negative pressure region depending on the location of the air passage 22. Yes, and more preferably 0.30 or less. The ratio may vary depending on the position of the cross section.

Note that the substrate holding member is schematically shown in the drawings, and the aspect ratio, spacing, number, etc. of the constituent elements of the substrate holding member are basically different from the actual design values. This is the same for all embodiments.
(function)

According to the substrate holding member as the first embodiment of the present invention, the substrate 1 is supported by the mounting table 4 in a state in which each of the plurality of lower surface protrusions 120 is in contact with the upper surface of the mounting table 4 . The substrate 1 is aligned with the mounting table 4 so that the opening of the ventilation path 42 formed in the mounting table 4 is included inside the inner annular lower surface convex portion 122 on the lower surface 102 of the substrate 1 .

A vacuum suction device (not shown) connected to the ventilation path 42 of the mounting table 4 in a state where the substrate W is placed on the upper end surface of at least a part of the upper surface protrusions 110 among the plurality of upper surface protrusions 110 , Air is sucked into the air passage 42 and a negative pressure region is formed in the air passage 22 of the base body 1 . As a result, a negative pressure region is formed in a space vertically sandwiched between the upper surface 101 of the substrate 1 and the lower surface of the substrate W via the air hole 21 communicating with the air passage 22 , and the substrate W is sucked toward the substrate 1 . force acts. By forming a negative pressure area in the ventilation path 22, a locally downward force is exerted on the ceiling portion 221, which is locally thin due to the formation of the ventilation path 22 on the upper surface 101 side of the base body 1. works.

However, the lower end portion 1210 of the ridge 121 extending in the designated direction parallel to the upper surface 101 of the base 1 and protruding downward from the ceiling portion 221 above the air passage 22 in the base 1 is the lower end portion 1210 of the base 1. (see Figure 1). For this reason, the ridges 121 function as a reinforcing structure for the base 1 to support the ceiling 221 from below with the mounting table 4 . Further, by extending the ridges 121 in the specified direction, the mechanical strength of the ceiling portion 221 is improved at least in the specified direction.

Thus, due to the formation of the negative pressure area in the ventilation path 22, when the suction force acts downward on the ceiling portion 221 of the base body 1, the depression of the ceiling portion 221 and the upper surface projection disposed on the ceiling portion 221 are suppressed. Downward displacement of 110 is suppressed or prevented. In addition, at least one of the plurality of upper surface protrusions 110 arranged on the ceiling portion 221 is supported from below by the protrusions 121 that are relatively unlikely to be recessed downward in the ceiling portion 221 of the base body 1 . The upper surface convex portion 110 of the portion is arranged.

For this reason, on the upper surface 101 of the base body 1, at least some of the upper surface protrusions 110 among the upper surface protrusions 110 arranged on the ceiling portion 221 are different from the other upper surface protrusions arranged at locations deviated from the ceiling portion 221. Displacement below 110 is avoided. Therefore, the substrate W is evenly brought into contact with the upper end surfaces 1100 of at least some of the upper surface projections 110 arranged on the ceiling portion 221 and the upper surface projections 110 arranged at locations outside the ceiling portion 221. It is possible to improve the flatness of the substrate W when it is held by suction on the substrate holding member. Then, on the front surface (upper surface) of the substrate W, predetermined processing such as exposure processing for forming a circuit of a desired pattern can be performed.
(Second embodiment)
(composition)

According to the substrate holding member as the second embodiment of the present invention shown in FIG. , a hollow space defined at least partially by a ceiling surface 2210 of the substrate 1 located between the upper surface 101 and the lower surface 102 of the substrate 1 and a floor surface 2220 of the substrate facing the ceiling surface 2210 . Specifically, the air passage 22 extends upward from an opening in the lower surface 102 of the base 1 , extends in a direction parallel to the upper surface 101 of the base 1 , and terminates inside the base 1 .

The shape of the hollow space in the cross section of the base body 1 with the direction of extension of the hollow space as the perpendicular is rectangular, trapezoidal, parallelogram, polygonal, semicircular, circular, semielliptical, elliptical, etc. It may be in the shape of any two-dimensional area enclosed by a closed curve. For example, when the ceiling surface 2210 has a substantially semi-cylindrical shape that opens downward and the floor surface 2220 has a substantially semi-cylindrical shape that opens upward, the ventilation path 22 extending in a substantially cylindrical shape is formed between the ceiling surface 2210 and the floor surface. 2220. The ventilation path 22 may be defined by both side surfaces in addition to the ceiling surface 2210 and the floor surface 2220 .

The substrate holding member further includes a ridge 121 extending in a specified direction (eg, X direction) parallel to the upper surface 101 of the base 1 and protruding downward from the ceiling 221 above the air passage 22 in the base 1, In addition, the lower end of the ridge 121 is in contact with or integrated with the floor surface 2220 . Note that the upper end of the ridge 121 that extends in the specified direction and protrudes upward from the floor 222 below the air passage 22 in the base 1 may be in contact with or integrated with the ceiling surface 2210 .
A groove corresponding to a hollow space is formed in each joining surface of two approximately flat-plate shaped compacts (or pre-sintered compacts), and a ridge protruding from the bottom of the groove is formed in at least one of the compacts. After that, the two molded bodies are fired and integrated in a state where the bonding surfaces are bonded to each other, thereby producing the substrate holding member of the second embodiment.
The structure other than the structure of the ventilation path 22 and the ridge 121 is the same as that of the substrate holding member of the first embodiment, so the same reference numerals are used and the description is omitted.
(function)

According to the substrate holding member as the second embodiment of the present invention, the formation of the negative pressure region in the air path 22 increases the thickness of the upper surface 101 side of the substrate 1 by the amount of the air path 22 formed. Even if a downward force acts on the ceiling portion 221 which is locally small, for the same reason as in the first embodiment, the substrate W is placed on the ceiling portion 221 at least part of the upper convex portion 110 and the ceiling portion. The substrate W is attracted and held by the substrate holding member in a state of uniformly abutting on the upper end surface 1100 of each of the upper surface protrusions 110 arranged at a location deviated from 221. At this time, the flatness of the substrate W is improved. planned. Then, on the surface (upper surface) of the substrate W, a predetermined process such as an etching process for forming a circuit of a desired pattern can be performed.

DESCRIPTION OF SYMBOLS 1. Base 4. Mounting table 21. Ventilation hole 22. Ventilation path 42. Ventilation path 101. Upper surface 102. Lower surface 110. Upper surface protrusion 114.. Annular upper surface protrusion 120.. Lower surface protrusion , 121... ridges, 122... inner annular lower surface convex part, 124... outer annular lower surface convex part, 221... ceiling part, 222... floor part, 2210... ceiling surface, 2220... floor surface, W... substrate (wafer).

Claims (4)

a plate-like substrate having an upper surface and a lower surface, a plurality of upper surface protrusions projecting upward from the upper surface of the substrate, and a recess recessed from the lower surface of the substrate; and one or more ventilation holes having openings in the upper surface of the base, wherein the protrusion protrudes downward from the ceiling above the ventilation path in the base. In the linear concave portion having a ridge, the lower end of the ridge being positioned at the same height as the lower surface or the lower end of the base, and the ridge forming the air passage, one or more (1) extend linearly, and in the arcuate recess forming the air passage, one or more ridges extend in an arc. The substrate holding member according to claim 1,
A substrate holding member, wherein at least a part of the upper surface protrusions arranged on the ceiling portion on the upper surface of the base body is arranged in a region in which the ridge exists. a flat substrate having an upper surface and a lower surface; a plurality of upper surface projections projecting upward from the upper surface of the substrate;
a ventilation path configured by a hollow space defined at least partially by a ceiling surface of the base body located between the upper surface and the lower surface of the base body and a floor surface of the base body facing the ceiling surface; a substrate holding member comprising one or more vent holes communicating with the path and having openings in the upper surface of the substrate,
The base has a ridge extending in the direction of a designated area parallel to the upper surface of the base and protruding downward from the ceiling above the air passage, and the lower end of the ridge extends to the floor surface. abutting or integral with, or
The base body has a ridge extending in the specified direction and protruding upward from a floor portion below the air passage, and an upper end of the ridge abuts the ceiling surface, One or more ridges extend linearly in the linear recesses forming the air passage, and one or more ridges extend linearly in the arc-shaped recesses forming the air passage. A substrate holding member characterized by extending in an arc shape . The substrate holding member according to claim 3,
A substrate holding member, wherein at least a part of the upper surface protrusions arranged on the ceiling portion on the upper surface of the base body is arranged in a region in which the ridge exists.

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