Semiconductor manufacturing equipment

Abstract

Semiconductor manufacturing apparatus, which detaches semiconductor chips (12a) from a saw foil (13) at a surface to which an approximately circular wafer (12) containing the semiconductor chips (12a) is attached, wherein the semiconductor chips (12a) are obtained by dividing the wafer (12) into small pieces by singulation, wherein the semiconductor manufacturing apparatus comprises: • a table (3) on which the wafer (12) is arranged over the saw foil (13), wherein the table (3) has a plurality of projections (10, 11, 17) which support the wafer (12); • a saw foil holder (7) which holds the saw foil (13);and a gas evacuation device which evacuates gases from a space between the table (3) and the saw film (13), wherein the plurality of projections (10, 11, 17) comprise a plurality of first projections (10) which each have a chamfered section which is chamfered in cross-section and an end which is arranged on a central section which, in a plan view, is an approximately circular region in the center of the table (3), and at least one second projection (11, 17) without a chamfered section which has an end which, in a plan view, is arranged on a circumferential section which surrounds the central section.

Description

Background of the invention Field of invention The present disclosure relates to a semiconductor manufacturing device. Description of the state of the art In steps for manufacturing a semiconductor device, a technology for singulating a wafer attached to a saw sheet is sometimes used to form semiconductor chips and to pick up each of the formed semiconductor chips from the saw sheet using a pick-up device. Japanese patent application disclosure no. JP 2008-103 493 A describes a technology for arranging a plurality of protrusions on a table (a device base) which holds semiconductor chips over a saw blade, for evacuating gases between the saw blade and the table to detach sections of the saw blade from the semiconductor chips that deviate from sections adjacent to the protrusions, and for picking up the semiconductor chips while reducing the adhesion between the saw blade and the semiconductor chips. Although the cited reference describes an adhesive layer as the saw blade, it also mentions an application of the saw blade instead of the adhesive layer. However, in the technology described in the cited reference, sometimes when gases are evacuated, small pieces (hereinafter referred to as unwanted chips) of a wafer, which are generated in a circumferential region of the wafer by singulation, are detached from the saw foil, fly off onto the semiconductor chips that are to become products, and damage the semiconductor chips. US 2013 / 0095613A1 discloses a manufacturing process for semiconductor devices and a manufacturing system for semiconductor devices. US 2007 / 0177125A1 discloses a substrate holding unit for receiving a process substrate and an exposure device equipped therewith. Summary The present disclosure discloses a task for providing a semiconductor manufacturing device which facilitates the removal of semiconductor chips from a saw foil and prevents unnecessary chips from flying away during the removal of the semiconductor chips. The semiconductor manufacturing apparatus according to the present disclosure is a semiconductor manufacturing apparatus which detaches semiconductor chips from a saw foil at a surface to which an approximately circular wafer containing the semiconductor chips is attached, wherein the semiconductor chips are obtained by dividing the wafer into small pieces by means of singulation, wherein the semiconductor manufacturing apparatus comprises: a table on which the wafer is arranged over the saw foil, wherein the table has a plurality of projections which support the wafer; a saw foil holder which holds the saw foil;and a gas evacuation device which evacuates gases from a space between the table and the saw film, wherein the plurality of projections comprises a plurality of first projections, each having a chamfered section which is chamfered in cross-section and an end which is arranged on a central section which, in a plan view, is an approximately circular region in the center of the table, and at least one second projection without a chamfered section which has an end which, in a plan view, is arranged on a circumferential section which surrounds the central section. According to the present disclosure, the plurality of protrusions arranged on the table comprises the plurality of first protrusions, each having a chamfered section that is chamfered in a cross-sectional view and an end arranged on a central section that is approximately a circular region in the center of the table in a top view, and at least one second protrusion without a chamfered section, which has an end arranged on a circumferential section that surrounds the central section in the top view. This provides advantages in terms of simplifying the removal of the semiconductor chips that overlie the central section in the top view from a saw-cut foil, while also preventing unnecessary chips that overlie the circumferential section in the top view from flying off. These and other tasks, features, aspects and advantages of the present invention will become clearer with reference to the following detailed description of the present invention in conjunction with the accompanying figures. Brief description of the characters Fig. 1 is a top view of a semiconductor manufacturing device according to embodiment 1; Fig. 2 is a cross-sectional view of the semiconductor manufacturing device according to embodiment 1; Fig. 3 is a top view of a part of the semiconductor manufacturing device according to embodiment 1; Fig. 4 is a cross-sectional view of a part of the semiconductor manufacturing device according to embodiment 1; Fig. 5 is a cross-sectional view of a part of the semiconductor manufacturing device according to embodiment 1; Fig. 6 is a cross-sectional view illustrating semiconductor manufacturing steps according to embodiment 1; Fig. 7 is a cross-sectional view illustrating the semiconductor manufacturing steps according to embodiment 1; Fig. 8 is a cross-sectional view illustrating the semiconductor manufacturing steps according to embodiment 1; Fig. 9 is a cross-sectional view illustrating the semiconductor manufacturing steps according to embodiment 1; Fig.Figure 10 is a cross-sectional view illustrating the semiconductor manufacturing steps according to embodiment 1; Figure 11 is a cross-sectional view illustrating the semiconductor manufacturing steps according to embodiment 1; Figure 12 is a top view of a rough schematic view of a wafer; Figure 13 is a top view of part of a semiconductor manufacturing apparatus according to embodiment 2; and Figure 14 is a cross-sectional view of part of the semiconductor manufacturing apparatus according to embodiment 2. Description of preferred embodiments In the present disclosure, a surface of the table on which semiconductor chips and a wafer are mounted is referred to as a top surface, and a surface opposite the top surface is referred to as a bottom surface. Furthermore, a direction from the bottom surface towards the top surface of the table is referred to as upward (an upward direction), and a direction opposite the upward direction is referred to as downward (a downward direction). A vertical direction is a direction towards the top surface of the table, and a lateral direction is a direction orthogonal to the vertical direction, that is, a direction parallel to the top surface of the table. A top view is a view taken from a direction perpendicular to the top surface of the table, and a cross-sectional view is a view taken from a direction parallel to the top surface of the table.If overhangs are arranged on the top of the table, a direction is defined based on a virtual top surface, which is a surface formed by connecting ends of the overhangs. [Version 1] First, an overview of a semiconductor fabrication device 101 according to embodiment 1 is described with reference to Figures 1 and 2. Figure 1 is a top view of the semiconductor fabrication device 101, and Figure 2 is a cross-sectional view of a cross-section AA of the semiconductor fabrication device 101 in Figure 1. As illustrated in Figures 1 and 2, the semiconductor fabrication device 101 comprises a housing 1, a table frame 2 arranged within the housing 1, a table 3 arranged within the table frame 2, and a wafer holder 7 arranged on top of the circumference of the housing 1. The housing 1, the table frame 2, the table 3, and the wafer holder 7 are approximately circular in a top view, so that they correspond to the shape of a wafer, which is approximately circular. A support hand, not illustrated, is provided above the table 3. The details are described below. The table 3 is an assembly section on which a wafer, divided into a plurality of semiconductor chips by singulation, is mounted over a saw-cut foil. A table top 3a, which is a surface of the table 3 on which the saw-cut foil is mounted, extends parallel to an X-direction, which is a first direction, and a Y-direction, which is a second direction orthogonal to the first direction, and it is shaped approximately like a circle that, in a top view, is larger than the wafer. In other words, the table top 3a is shaped approximately like a circle, which has an outer peripheral edge that has a larger diameter than the wafer, which is approximately circular. Although the present disclosure describes an example in which the wafer and the table are approximately circular, the shape is not limited to an approximate circle, but can, for example, be a polygon or an oval. Furthermore, the table surface 3a has a central section 3a1, which is an approximately circular central region, and a circumferential section 3a2, which is a region surrounding the central section 3a1. As illustrated in Fig. 2, first projections 10 are arranged on the central section 3a1, and a second projection 11 is arranged on the circumferential section 3a2. When a wafer attached to a saw sheet is mounted on the table 3, the ends of the first projections 10 and the second projection 11 therefore abut the saw sheet and support the wafer through the saw sheet. Details of the first projections 10 and the second projection 11 will be described later with reference to other figures. The table 3 has a suction opening 4 that extends through the table top 3a to a table underside 3b, which is opposite the table top 3a. The suction opening 4 is open on the table top 3a and is connected to one end of a suction tube (not shown) on the table underside 3b. The other end of the suction tube is connected to a vacuum pump (not shown). When the vacuum pump is activated, air is drawn in from above the table top 3a. Therefore, when a wafer is mounted on the table 3 over a saw sheet and the vacuum pump is activated, gases are evacuated from the space between the table top 3a and the saw sheet. Instead of the suction opening 4, the vacuum pump, and the suction tube, the semiconductor manufacturing device 101 may have a gas evacuation device that can evacuate gases from the space between the table top 3a and the saw sheet. The table frame 2 is a frame that encloses the table 3, for example, a cylindrical housing. A region enclosed by the table frame 2 includes a central axis 5, one end of which is connected to a lower section of the table 3 and the other end of which is connected to a table drive 6, which has a motor. Controlling the motor of the table drive 6 can move the table 3 in a Z-direction, which is a third direction orthogonal to the X and Y directions. The saw film holder 7 is mounted in a ring-like fashion on top of the circumference of the housing 1 and is a mechanism that serves to hold a saw film to which a wafer is attached when the saw film is mounted on the table 3, and to pull the saw film in a direction towards its outer peripheral edge, that is, outwards from the centers of the approximately circular table 3 and the wafer. Specifically, the saw film holder 7 comprises a frame support 8, a frame pressure part 9, and a cylinder (not shown) that moves the frame pressure part 9 up and down. The frame, which is attached to the circumferential section of the saw film, can be enclosed and held by the frame support 8 and the frame pressure part 9. Since the surface of the frame support 8 in the Z-direction, which borders the saw film, is lower than the ends of the first overhangs 10 and the second overhang 11, which are arranged on the table top 3a, the frame is held lower than the ends of the first overhangs 10 and the second overhang 11 when holding the saw film. As a result, the saw film holder 7 stretches the saw film in a direction from the center of the table 3 to the outer peripheral edge. Next, the first projections 10, which are arranged on the central section 3a1, and the second projection 11, which is arranged on the circumferential section 3a2 in the table top 3a, are described in detail. Fig. 3 is a top view illustrating section B in Fig. 1, that is, an enlarged view of part of a boundary between the central section 3a1 and the circumferential section 3a2 in the table 3, viewed from above. Fig. 4 is a cross-sectional view of a cross-section CC in Fig. 3, and it is an enlarged view of section D in Fig. 2. Although the boundary between the central section 3a1 and the circumferential section 3a2 and the outer peripheral edge of the circumferential section 3a2 are circular segments, Fig. 3 simply illustrates the boundary of the outer peripheral edge with straight lines. Figs. 3 and 4 omit the table frame 2. As illustrated in Figures 3 and 4, the plurality of first projections 10 are arranged such that their respective ends protrude from the central section 3a1 of the table surface 3a. Furthermore, the second projection 11 is arranged such that an annular and continuous end projects from the circumferential section 3a2 of the table surface 3a. In other words, the ends of the first projections 10 and the second projection 11 are each located on the central section 3a1 and the circumferential section 3a2, respectively. Moreover, the ends of the first projections 10 and the second projection 11 are of the same height. In the present disclosure, the ends of the first projections 10 and the second projection 11 represent the ends of projections that protrude from the table surface 3a.The ends of the first overhang 10 and the second overhang 11 should have heights that provide the necessary flatness to allow a wafer to be held over a saw sheet. Therefore, it is not always necessary for the first overhang 10 and the second overhang 11 to be the same height. The first projections 10, which are arranged on the central section 3a1, are described in more detail below. As illustrated in Figures 3 and 4, the plurality of first projections 10 are arranged in a lattice structure such that, in a top view, two of the ends have a distance Px, which is a distance in the X-direction, and two of the other ends have a distance Py, which is a distance in the Y-direction. The distance Px is equal to the distance Py in embodiment 1. Thus, the first projections 10 are arranged in a square lattice structure. The arrangement positions of the first projections 10 in a top view are not limited to those shown in Figure 3. The positions should be determined in a timely manner, taking into account, for example, the size of each semiconductor chip formed by singulating a wafer, deformation properties, the adhesion of a saw sheet, and the suction capacity of the gas evacuation device. For example, a semiconductor chip intended for use as a power semiconductor device would be approximately 5 mm to 15 mm in size. The distance between the ends of any two adjacent first projections 10 corresponding to semiconductor chips of this size should be 2 mm or less, and preferably 0.5 mm to 1.5 mm. If the distance between the ends of any two adjacent first projections 10 is too large, the number of points supporting a semiconductor chip will be reduced. If the distance is too small, the distances between points supporting a semiconductor chip will be shorter. In either of these cases, a peel defect will readily occur, which is a defect in which semiconductor chips cannot be peeled from a saw foil. The arrangement of the first projections 10 is not limited to rectangular lattice structures, including the square lattice structure.The first protrusions 10 should be arranged at the previously mentioned intervals. The first overhang 10 is shaped like a square pyramid and has a tapered portion that tapers towards the end in a cross-sectional view. Since the ends of the first overhang 10 are sections adjacent to a saw sheet, the area of ​​these sections is preferably extremely small, and each section has a shape that abuts a point to release the semiconductor chips from the saw sheet. However, if the ends are pointed, they may scratch or damage the saw sheet or the semiconductor chips when they come into contact with it. Therefore, the end of the first overhang 10 can, for example, be chamfered to form a plane parallel to the table surface 3a with the smallest possible extent, as illustrated in Figures 3 and 4. The end can, for example, be chamfered to form a hemispherical shape. Although the first projection 10, as illustrated in Figs. 3 and 4, is shaped like a square pyramid, the shape is not limited to this and can be a circular cone or a pyramid such as a triangular pyramid. The first projection 10 can have a chamfered section at one end with the shape of a pyramid or a circular cone, and a base section with the shape of a prism or a circular cylinder closer to the base than to the chamfered section. Next, the second projection 11, which is arranged on the circumferential section 3a2 of the table surface 3a, will be described in detail. As illustrated in Figs. 3 and 4, the second projection 11 is arranged on the circumferential section 3a2 of the table surface 3a such that its end protrudes from the table surface 3a. The second projection 11 is annular, surrounding the central section 3a1 in a top view of Fig. 3, and it is not tapered in the Z-direction but has a rectangular shape in a cross-sectional view of Fig. 4. In other words, the end of the second projection 11 has the shape of a plane parallel to the table surface 3a. The size of the respective central section 3a1, on which the first protrusions 10 are arranged, and of the circumferential section 3a2, on which the second protrusions 11 are arranged on the table surface 3a, can be changed as needed, depending on the size of a wafer to be produced and the size and position of a semiconductor chip formed in the wafer. Specifically, the circumferential section 3a2 should be defined such that it corresponds to the positions of unnecessary chips, which are small pieces of a wafer produced by singulation in a circumferential region of the wafer and are not intended to become products. A region located further inward than the circumferential section 3a2 should be defined on the central section 3a1. Therefore, the second protrusion 11 and the first protrusions 10 should each be arranged on the circumferential section 3a2 and the central section 3a1, respectively.The unnecessary chips will be described later when the effects of the present disclosure are described. Currently, the sizes of wafers used in semiconductor device manufacturing are standardized. Examples of diameters for the outer peripheral edges of wafers, which are approximately circular and do not include orientation flats, are 100 mm, 150 mm, 200 mm, 300 mm, and 450 mm. During semiconductor device manufacturing, unnecessary chips, which are not intended for use in products, are easily generated, for example, in regions 3 to 5 mm inward from the outer peripheral edges of the wafer. At the same time, these regions often fail to meet product specifications due to issues such as variations in the manufacturing process. Sometimes, semiconductor chips intended for use in products are not located in these inefficient regions. In light of this, the central section 3a1, for example, is approximately circular in shape, with a diameter of one of 92 ± 2 mm, 142 ± 2 mm, 192 ± 2 mm, 292 ± 2 mm, and 442 ± 2 mm, relative to a wafer of each of the standardized sizes. Then, the first projections 10 should be arranged such that the end of the outermost first projection 10 is located in a region 2 mm or less from the outer peripheral edge of the central section 3a1 in a direction from the outer peripheral edge to the center. In other words, assuming that a distance between the center of the central section 3a1 and one of the ends of the first projections 10, which are furthest from the center of the central section 3a1, is a first distance, the first distance should be one of 45 ± 2 mm, 70 ± 2 mm, 95 ± 2 mm, 145 ± 2 mm, and 220 ± 2 mm. Furthermore, the second overhang 11 should be arranged such that the edge of the second overhang 11, which is furthest from the center of the central section 3a1 in a top view, is located further out than the outer peripheral edge of the wafer of each of the standardized sizes. In other words, assuming that a distance between the center of the central section 3a1 and the edge of the second projection 11, which is furthest from the center of the central section 3a1, is to be a second distance, the second distance should correspond to 50 mm or longer if the first distance corresponds to 45 ± 2 mm, 75 mm or longer if the first distance corresponds to 70 ± 2 mm, 100 mm or longer if the first distance corresponds to 95 ± 2 mm, 150 mm or longer if the first distance corresponds to 145 ± 2 mm, and 225 mm or longer if the first distance corresponds to 220 ± 2 mm.These arrangements allow semiconductor chips to overlap the central section 3a1, and allow unnecessary chips to overlap the circumferential section 3a2. The first projections 10 and the second projection 11 can be formed by attaching components to the table 3, which are to become projections and are produced separately, or they can be formed directly on the table 3 by processing the table surface 3. If the first projections 10 and the second projection 11 are components that are separable from the table 3 and are attached to the table 3, for example, using screws, the first projections 10 and the second projection 11 can be individually detached from the table 3, and their shapes, spacing, and number of projections, etc., can be changed according to the circumstances. Although the table 3 has the intake opening 4 as illustrated in Figures 3 and 4, a plurality of intake openings 4 can be distributed over a wide area within a plane of the table surface 3a. The distributed intake openings 4 can evacuate gases more evenly from the space between the table surface 3a and the saw film. Furthermore, the intake opening 4 can be circular, rectangular, or slot-shaped in a top view. Furthermore, vacuum grooves 15, which serve as exit paths for gas evacuation, can be formed between the first projections 10 and between each of the first projections 10 and the second projection 11 on the table surface 3a to effectively evacuate gases. Fig. 5 is a cross-sectional view illustrating a cross-section of the table 3 in Fig. 4 to which the vacuum grooves 15 have been added. The vacuum grooves 15 can be configured to extend in the X and Y directions or to form a lattice structure. Alternatively, one of the vacuum grooves 15 can be arranged for a plurality of projections in a cross-sectional view. The details of the functions of the vacuum grooves 15 will be described later when a method for fabricating a semiconductor device using the semiconductor fabrication apparatus 101 is described. Finally, a carrier hand (not illustrated) is described. The carrier hand is a receiving device that picks up each of the semiconductor chips attached to a saw foil arranged on table 3. The carrier hand has, for example, an arm with one end to which an adsorption pad is attached, and it can adsorb and hold each semiconductor chip by means of the adsorption pad. The carrier hand can be part of the semiconductor manufacturing device 101, be integrated into another device, for example, a manufacturing device in the next step, or be integrated into a single transport robot. Before describing the effects and advantages of the semiconductor manufacturing device 101 according to embodiment 1, the method for manufacturing a semiconductor device using the semiconductor manufacturing device 101 will first be described. The method for manufacturing a semiconductor device described here corresponds to manufacturing steps that include separating each of the semiconductor chips, which are formed by singulating a wafer, from a saw sheet and picking up the semiconductor chip. Fig. 6 is a cross-sectional view that schematically illustrates the manufacturing steps after the transport step. Furthermore, Fig. 7 is an enlarged cross-sectional view of section E in Fig. 6. First, the transport step is performed to move the wafer 12 and the saw foil 13 into the semiconductor manufacturing machine 101. Although Fig. 6 simply illustrates the wafer 12, the wafer 12, which is attached to the top surface of the saw foil 13, is actually singulated in a singulation step prior to the transport step. In other words, the wafer 12 is divided into semiconductor chips 12a, which are to become products; waste chips 12b, which are identical in size to the semiconductor chips 12a but are not to become products; and waste chips 12c, which are smaller than the semiconductor chips 12a and are not to become products, as illustrated in Fig. 7.Although the unnecessary chips 12b are identical in size to the semiconductor chips 12a, the unnecessary chips 12b, which are located near the outer peripheral edge of the wafer 12, are not intended as products due to quality management risks. These chips, which remain attached to the saw foil 13, are transported to the semiconductor manufacturing device 101 during the transport step to be supported by and positioned on the first overhangs 10 and the second overhang 11 on the table 3 by the saw foil 13. The saw film 13, for example, is an adhesive film with surface adhesion, a resin film obtained by adding a pressure-sensitive acrylate adhesive to a base material containing polyolefin. The saw film 13 exhibits an adhesive force high enough to secure the wafers 12 so that they do not move when singulated, and to further secure the semiconductor chips 12a, the unwanted chips 12b, and the unwanted chips 12c, which were separated by singulation, so that they do not detach and scatter. A frame 14 is attached to an upper surface of a region outside of a region where the wafer 12 is attached to the saw foil 13. The frame 14 is used when the saw foil 13 is transported and held in the semiconductor manufacturing device 101. Fig. 8 is a cross-sectional view illustrating the manufacturing steps after the saw foil holding step. Furthermore, Fig. 9 is an enlarged cross-sectional view of section F in Fig. 8. After the transport step, the saw foil holding step is performed to hold the saw foil 13 and pull it outwards. After the saw foil 13 has been transported into the semiconductor manufacturing device 101 during the transport step, the frame pressure part 9 of the saw foil holder 7, which is attached to a circumferential section of the housing 1, moves downwards to enclose the frame 14 between the frame support 8 and the frame pressure part 9 to hold the saw foil 13. Although the saw foil 13 is held without movement while positioned on the table top 3a in the saw foil holding step, the saw foil 13 is pulled from the centers of the approximately circular table 3 and the wafer toward the outer peripheral edge because the frame 14 is held in a position lower than that of the table top 3a. This enlarges the elastic saw foil 13 in a direction toward the outer peripheral edge and widens the gaps between the semiconductor chips 12a, the unwanted chips 12b, and the unwanted chips 12c that are adjacent to each other, thus preventing malfunction or interference between the chips when the chips are picked up. Fig. 10 is a cross-sectional view schematically illustrating the manufacturing steps after the peeling step. Furthermore, Fig. 11 is an enlarged cross-sectional view of section G in Fig. 10. After the saw foil holding step, the peeling step is performed to remove the semiconductor chips 12a from the saw foil 13. When the vacuum pump is operated while the saw foil 13 is held, the vacuum pump evacuates gases from the space between the saw foil 13 and the table surface 3a. As illustrated in Fig. 11, sections of the saw foil 13 that deviate from sections adjacent to the ends of the first overhangs 10 and the second overhang 11 are drawn in and deformed in a direction approaching the table surface 3a. Here, the first projections 10 are arranged on the central section 3a1 of the table surface 3a. The semiconductor chips 12a, which are to become products, are mainly arranged in the central section 3a1. When the vacuum pump evacuates gases, the sections of the saw foil 13 that deviate from the sections adjacent to the ends of the first projections 10 are deformed in the direction approaching the table surface 3a, and they are detached from the back of the semiconductor chips 12a. If the spacing for arranging the first protrusions 10 is large relative to the size of each semiconductor chip 12a, the number of first protrusions 10 adjacent to the semiconductor chips 12a decreases. In such a case, deformation of the saw foil 13 causes the semiconductor chips 12a to fall and tilt between the adjacent first protrusions 10, sometimes resulting in a defect when removing the saw foil 13. Conversely, if the spacing for arranging the first protrusions 10 is small relative to the size of each semiconductor chip 12a, the region between the adjacent first protrusions 10 narrows. This inhibits deformation of the saw foil 13 and sometimes causes an error in the removal of the saw foil 13. Since small pieces such as unnecessary chips 12c are not arranged in the central section 3a1, distances for arranging the first protrusions 10 can be optimized in accordance with the size of the semiconductor chip 12a. In contrast, the second projection 11 is arranged on the circumferential section 3a2 of the table surface 3a. The circumferential section 3a2 mainly contains the unwanted chips 12b and 12c, which are not intended to become products. In the circumferential section 3a2, the saw foil 13 abuts the surface of the end of the second projection 11 and is not deformed. Therefore, the unwanted chips 12b and 12c are hardly detached from the saw foil 13. In particular, since the annular and continuous second projection 11 is arranged and abuts the wafer 12 on the flat surface in embodiment 1, the unwanted chips 12c, which are attached to the saw foil 13, can be held in place without being detached, even if the size of each unwanted chip 12c is small. In Fig. 11, the saw foil 13 follows the shape of the first projections 10 and is completely adsorbed onto the first projections 10 in the central section 3a1. However, it is not always necessary for the saw foil 13 to be completely adsorbed in this way. Instead, the sections of the saw foil 13 that deviate from the sections adjacent to the ends of the first projections 10 should be deformed in the direction approaching the table surface 3a until the sections of the saw foil 13 are detached from the lower surfaces of the semiconductor chips 12a. The saw foil 13, which is completely adsorbed onto the table surface 3a, sometimes obstructs the intake opening 4, causing a region where gases are not sufficiently evacuated to remain in a portion of the plane of the table surface 3a. In such a case, the vacuum grooves 15 in Fig. 5 provide escape paths through which air is released during gas evacuation, even when the saw foil 13 is completely adsorbed onto the first projections 10 in the central section 3a1. These vacuum grooves 15, which extend over a wide region of the table surface 3a, allow gases to be evacuated more uniformly from the space between the table surface 3a and the saw foil 13 in a single plane. After the peeling step, a pick-up step is performed to pick up each of the semiconductor chips 12a from the saw foil 13 and to transport the semiconductor chip 12a out of the semiconductor manufacturing device 101. The pick-up step, for example, involves adsorbing the top surface of each semiconductor chip 12a using the carrier hand with the adsorption pad, lifting the semiconductor chip 12a upwards, peeling the semiconductor chip 12a from the saw foil 13, and placing the semiconductor chip 12a in a support frame for transport to the next step. During the peeling step prior to the pick-up step, sections of the saw foil 13 that differ from the sections adjacent to the ends of the first protrusions 10 are peeled away from the semiconductor chips 12a. Thus, the semiconductor chips 12a are only held and attached to the sections of the saw foil 13 that border the ends of the first overhangs 10.Therefore, the carrier hand can easily pick up each of the semiconductor chips 12a with a small force. The effects of the semiconductor manufacturing device 101 according to embodiment 1 are described. Before describing the effects, the structure of the wafer 12 is described in detail. Fig. 12 is a top view of the wafer 12, which is attached to the saw foil 13 and separated. As shown in Fig.As illustrated in Figure 12, the wafer 12, which is attached to the upper surface of the saw foil 13, is singulated during the singulation step prior to the transport step along the singulation lines extending in the X direction and the Y direction, which is orthogonal to the X direction, to separate it into the rectangular semiconductor chips 12a, which will become products; the unwanted chips 12b, which are also rectangular and have the same size as the semiconductor chips 12a but are not intended to become products; and the unwanted chips 12c, which are not rectangular, have a smaller size than the semiconductor chips 12a, and are not intended to become products. Regions between the semiconductor chips 12a, the unwanted chips 12b, and the unwanted chips 12c are singulation lines. After the wafer 12 has been singulated, these regions are air gaps from which the wafer 12 has been removed. In the fabrication of a semiconductor device, an approximately circular boundary 16 is defined in the wafer 12. A central region within the boundary 16 is designated as an effective region in which products can be placed. Furthermore, a circumferential region outside the boundary 16 is designated as an ineffective region in which chips intended to become products cannot be placed without risk to quality management, which could be caused, for example, by variations in the manufacturing process. As illustrated in Fig. 12, the unnecessary chips 12b, although identical in size to the semiconductor chips 12a, are not intended to become products because all or some of the chips lie in the ineffective region outside the boundary 16.Furthermore, the unnecessary chips 12c are not to become products, since they are not only located at the outermost perimeter of wafer 12 and in the ineffective region outside boundary 16, but also because they are smaller than the semiconductor chips 12a. For example, the width of the perimeter region of wafer 12 varies depending on the product specification. The width is, for instance, approximately between 3 and 5 mm. In other words, boundary 16 is roughly circular, with a diameter approximately between 6 and 10 mm, which is smaller than the approximately circular wafer 12. In the semiconductor manufacturing device 101, the first protrusions 10 with tapered sections are arranged on the central section 3a1 of the table surface 3a, and the second protrusion 11 without a tapered section is arranged on the circumferential section 3a2 of the table surface 3a. The first protrusions 10 abut the semiconductor chips 12a at respective points in the central section 3a1. This arrangement has the effect that the semiconductor chips 12a are held by the first protrusions 10 without tilting due to deformation of the saw foil 13, and the semiconductor chips 12a can be easily detached from the saw foil 13 in regions between the points where the first protrusions 10 abut the semiconductor chips 12a. In contrast, the second overhang 11, without a tapered section on the circumferential section 3a2, borders the unnecessary chips 12b and 12c in the circumferential region of the wafer 12 at a plane. This creates an effect that prevents deformation of the saw foil 13 and unintentional detachment of the unnecessary chips 12b and 12c from the saw foil 13 during gas evacuation. In particular, since the second overhang 11 borders the unnecessary chips 12c, which are smaller than the semiconductor chips 12a, unintentional detachment of the unnecessary chips 12c is prevented. Next, the advantages of the semiconductor manufacturing device 101 according to embodiment 1 will be described. The unwanted chips 12b and 12c generated during singulation are never used as products and are separately conveyed to a disposal step while attached to the saw foil 13. Since the unwanted chips 12c are smaller than the semiconductor chips 12a, they tend to be unintentionally detached from the saw foil 13. In particular, when gases are evacuated while the unwanted chips 12c are adjacent to tapered protrusions at respective points, as in conventional technologies, deformation of the saw foil 13 sometimes causes the unwanted chips 12c to detach from the saw foil 13.When the unnecessary chips 12c are detached, a chip-flight malfunction occurs, that is, the unnecessary chips 12c fly off onto the semiconductor chips 12a, which are intended to become products that are located around the unnecessary chips 12c, and they damage the semiconductor chips 12a. The semiconductor manufacturing device 101 according to embodiment 1 has the first projections 10 with tapered sections on the central section 3a1 of the table top 3a to correspond to a central region within the boundary 16 of the wafer 12. The first projections 10 offer advantages in terms of facilitating the removal of the semiconductor chips 12a, which are arranged in the central section of the wafer 12, from the saw foil 13 and in preventing removal defects. The semiconductor manufacturing device 101 further has the second projection 11 without a tapered section on the circumferential section 3a2 of the table top 3a to correspond to the circumferential region of the boundary 16. The second protrusion 11 provides advantages in terms of reducing the unintentional detachment of the unnecessary chips 12c in the circumferential region of the wafer 12 and preventing a chip flight malfunction. [Version 2] An overview of a semiconductor manufacturing device according to embodiment 2 is described with reference to Figures 13 and 14. Figure 13 is a top view illustrating section H, which is part of a boundary between the central section 3a1 and the circumferential section 3a2 of the table 3, viewed from above. Section H corresponds to section B in Figure 1 according to embodiment 1, and Figure 13 corresponds to Figure 3 according to embodiment 1. Figure 14 is a cross-sectional view of a cross-section II in Figure 13, and it corresponds to Figure 4 according to embodiment 1. Although the boundary between the central section 3a1 and the circumferential section 3a2 and the outer peripheral edge of the circumferential section 3a2 are circular segments, Figure 3 simply illustrates the boundary of the outer peripheral edge with straight lines. The semiconductor manufacturing device according to embodiment 2 evacuates gases from the space between the table surface 3a and the saw foil 13 in order to detach the semiconductor chips 12a from the saw foil 13, similar to embodiment 1. The semiconductor manufacturing device according to embodiment 1 has the first projections 10 with the tapered sections on the central section 3a1 of the table surface 3a and the second projection 11, which is annular and continuous in a top view, without a tapered section on the circumferential section 3a2 of the table surface 3a. In contrast, the semiconductor manufacturing device according to embodiment 2 has the first projections 10 with the tapered sections on the central section 3a1 of the table surface 3a similar to embodiment 1, and a plurality of second projections 17 without a tapered section on the circumferential section 3a2 of the table surface 3a. The details are described below.The overlapping description regarding the same structures as that according to embodiment 1 may be omitted. As illustrated in Figs. 13 and 14, the first projections 10 are arranged on the central section 3a1 of the table surface 3a such that their respective ends protrude from the table surface 3a, similar to embodiment 1. The arrangement of the first projections 10 is identical to that according to embodiment 1. The distance between adjacent first projections 10 should be 2 mm or less, and preferably 0.5 mm to 1.5 mm. Furthermore, the multiple second projections 17, each shaped like a square rod, are arranged on the circumferential section 3a2 of the table surface 3a such that their respective ends protrude from the table surface 3a. The lengths of the spaces between the adjacent second projections 17, that is, gaps Sx and Sy, each correspond to 1 mm or less, which are dimensions smaller than the distance Px and the distance Py of the first projections 10 on the central section 3a1. The shape of the respective second projections 17 is not limited to a square rod, but can be a circular cylinder or a prism, such as a triangular rod. The ends of the first overhangs 10 and the second overhangs 17, for example, have the same height. In the present disclosure, the ends of the first overhangs 10 and the second overhangs 17 represent the ends of the overhangs that project from the table top 3a. The ends of the first overhangs 10 and the second overhangs 17 should have heights that provide the flatness necessary to hold the wafer 12 over the saw film 13. Therefore, it is not always necessary for the first overhangs 10 and the second overhangs 17 to have the same height. The arrangement positions of the first projections 10 and the second projections 17 according to embodiment 2 are identical to those of the first projections 10 and the second projections 11 according to embodiment 1. In other words, the first projections 10 should be arranged such that the first distance, which is a distance between the center of the central section 3a1 and the end of the first projection 10 furthest from the center of the central section 3a1 in a plan view, corresponds to one of 45 ± 2 mm, 70 ± 2 mm, 95 ± 2 mm, 145 ± 2 mm, and 220 ± 2 mm to correspond with the wafer of each of the standardized sizes.Furthermore, the second gaps 17 should be arranged such that the second gap, which is a distance between the center of the central section 3a1 and the edge of the second projection 17, which is furthest from the center of the central section 3a1 in a plan view, corresponds to 50 mm or longer if the first gap corresponds to 45 ± 2 mm, 75 mm or longer if the first gap corresponds to 70 ± 2 mm, 100 mm or longer if the first gap corresponds to 95 ± 2 mm, 150 mm or longer if the first gap corresponds to 145 ± 2 mm, and 225 mm or longer if the first gap corresponds to 220 ± 2 mm. The advantages of the semiconductor manufacturing device according to embodiment 2 are described. The central section 3a1 according to embodiment 2 is structurally identical to that of embodiment 1 and exhibits an effect that facilitates the easy detachment of the semiconductor chips 12a from the saw foil 13 (i.e., detachment defects are minimal) in regions adjacent to the first protrusions 10 on the central section 3a1. On the circumferential section 3a2, the second protrusions 17, without a tapered section, abut the unwanted chips 12b and 12c in a circumferential region of the wafer 12 at a single plane. Thus, the evacuation of gases prevents deformation of the saw foil 13 in contact with the unwanted chips 12b and 12c. This creates an effect in terms of preventing the unnecessary chips 12b and the unnecessary chips 12c from unintentionally detaching from the saw foil 13. The second projections 17 are not continuous on the circumferential section 3a2 according to embodiment 2. The adjacent second projections 17 have a gap between them. This gap acts as an exit path for gas evacuation and prevents the formation of air pockets on the end surfaces of the second projections 17. Adherence of the end surfaces of the second projections 17 to the saw film 13 without a gap prevents unintentional detachment of the second projections 17 from the saw film 13. Larger gaps between the second projections 17 can deform the saw film 13, as the saw film 13 enters the gap during gas evacuation. This can unintentionally detach the unwanted chips 12b and 12c from the saw film 13.Forming the lengths of the gaps between the adjacent second projections 17, that is, the gaps Sx and Sy with 1 mm or less, produces advantages in terms of reducing deformation of the saw foil 13, preventing the removal of the unnecessary chips 12b and the unnecessary chips 12c, and preventing chip flight malfunction. Several embodiments of the disclosure described above are provided as examples. These embodiments may be omitted, modified, or altered without departing from the spirit and scope of the disclosure. The embodiments may be combined. A summary of different aspects of the present revelation is described below in the appendices. [Annex 1] Semiconductor manufacturing apparatus for separating semiconductor chips from a saw sheet at a surface to which an approximately circular wafer containing the semiconductor chips is attached, wherein the semiconductor chips are obtained by dividing the wafer into small pieces by singulation, the semiconductor manufacturing apparatus comprising: a table on which the wafer is arranged over the saw sheet, the table having a plurality of protrusions which support the wafer; a saw sheet holder which holds the saw sheet;and a gas evacuation device which evacuates gases from a space between the table and the saw film, wherein the plurality of projections comprises a plurality of first projections, each having a tapered section which is tapered in a cross-sectional view and an end which is arranged on a central section which in a plan view is an approximately circular region in a center of the table, and at least one second projection without a tapered section which has an end which in a plan view is arranged on a circumferential section which surrounds the central section. [Annex 2] Semiconductor manufacturing apparatus according to Annex 1, wherein the at least one second protrusion has a second protrusion which is annular and continuous around the central section in the top view. [Annex 3] Semiconductor manufacturing apparatus according to Annex 1, wherein the at least one second protrusion has a plurality of second protrusions which are not continuous in plan view. [Annex 4] Semiconductor manufacturing apparatus according to Annex 3, wherein the length of a gap between two adjacent second protrusions is 1 mm or less. [Annex 5] Semiconductor manufacturing apparatus according to any one of Annexes 1 to 4, wherein the distance between the ends of the two adjacent first projections is 2 mm or less. [Annex 6] Semiconductor manufacturing apparatus according to any one of Annexes 1 to 5, wherein the semiconductor chips are arranged in a central region of the wafer, unnecessary chips, which are not the semiconductor chips and are small pieces, are arranged in a circumferential region surrounding the central region, and the end of at least one of the first protrusions overlaps the semiconductor chips and the end of at least one second protrusion overlaps the unnecessary chips in the top view when the wafer is placed on the table. [Annex 7] Semiconductor manufacturing apparatus according to any one of Annexes 1 to 6, wherein a first distance, which is a distance between the center of the central section and the end of one of the first projections furthest from the center of the central section in a top view, corresponds to one of 45 ± 2 mm, 70 ± 2 mm, 95 ± 2 mm, 145 ± 2 mm, and 220 ± 2 mm. [Annex 8] Semiconductor manufacturing apparatus according to Annex 7, wherein a second distance, which is a distance between the center of the central section and an edge of the at least one second projection which is furthest from the center of the central section in plan view, corresponds to 50 mm or longer if the first distance corresponds to 45 ± 2 mm, 75 mm or longer if the first distance corresponds to 70 ± 2 mm, 100 mm or longer if the first distance corresponds to 95 ± 2 mm, 150 mm or longer if the first distance corresponds to 145 ± 2 mm, and 225 mm or longer if the first distance corresponds to 220 ± 2 mm. [Annex 9] Semiconductor manufacturing apparatus according to any one of Annexes 1 to 8, wherein the saw foil holder has a function for stretching the saw foil in a direction from the center of the table to an outer peripheral edge of the table. [Annex 10] Semiconductor manufacturing apparatus according to any one of Annexes 1 to 9 comprising a receiving device which receives each of the semiconductor chips from the table.

Claims

Semiconductor manufacturing apparatus, which detaches semiconductor chips (12a) from a saw foil (13) at a surface to which an approximately circular wafer (12) containing the semiconductor chips (12a) is attached, wherein the semiconductor chips (12a) are obtained by dividing the wafer (12) into small pieces by singulation, wherein the semiconductor manufacturing apparatus comprises: • a table (3) on which the wafer (12) is arranged over the saw foil (13), wherein the table (3) has a plurality of projections (10, 11, 17) which support the wafer (12); • a saw foil holder (7) which holds the saw foil (13);and a gas evacuation device which evacuates gases from a space between the table (3) and the saw film (13), wherein the plurality of projections (10, 11, 17) comprise a plurality of first projections (10) which each have a chamfered section which is chamfered in cross-section and an end which is arranged on a central section which, in a plan view, is an approximately circular region in the center of the table (3), and at least one second projection (11, 17) without a chamfered section which has an end which, in a plan view, is arranged on a circumferential section which surrounds the central section. Semiconductor manufacturing apparatus according to claim 1, wherein the at least one second protrusion (11) has a second protrusion which is annular and continuous around the central section in the top view. Semiconductor manufacturing apparatus according to claim 1, wherein the at least one second protrusion has a plurality of second protrusions (17) which are not continuous in the top view. Semiconductor manufacturing apparatus according to claim 3, wherein the length of a gap between two adjacent second projections (17) corresponds to 1 mm or less. Semiconductor manufacturing apparatus according to any one of claims 1 to 4, wherein the distance between the ends of two adjacent first projections (10) is 2 mm or less. Semiconductor manufacturing apparatus according to any one of claims 1 to 5, wherein the semiconductor chips (12a) are arranged in a central region of the wafer (12), unnecessary chips (12b, 12c), which are not the semiconductor chips (12a) and are small pieces, are arranged in a circumferential region surrounding the central region, and the end of at least one of the first protrusions (10) overlaps the semiconductor chips (12a) and the end of at least one second protrusion (11) overlaps the unnecessary chips (12b, 12c) in the top view when the wafer (12) is arranged on the table (3). Semiconductor manufacturing apparatus according to any one of claims 1 to 6, wherein a first distance, which is a distance between the center of the central section and the end of one of the first projections (10) which is furthest from the center of the central section in a top view, corresponds to one of 45 ± 2 mm, 70 ± 2 mm, 95 ± 2 mm, 145 ± 2 mm, and 220 ± 2 mm. Semiconductor manufacturing apparatus according to claim 7, wherein a second distance, which is a distance between the center of the central section and an edge of the at least one second projection (17) which is furthest from the center of the central section in plan view, corresponds to 50 mm or longer if the first distance corresponds to 45 ± 2 mm, 75 mm or longer if the first distance corresponds to 70 ± 2 mm, 100 mm or longer if the first distance corresponds to 95 ± 2 mm, 150 mm or longer if the first distance corresponds to 145 ± 2 mm, and 225 mm or longer if the first distance corresponds to 220 ± 2 mm. Semiconductor manufacturing apparatus according to any one of claims 1 to 8, wherein the saw foil holder (7) has a function for stretching the saw foil (13) in a direction from the center of the table (3) to an outer peripheral edge of the table (3). Semiconductor manufacturing apparatus according to one of claims 1 to 9 comprising a receiving device which receives each of the semiconductor chips (12a) from the table (3).

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