UV irradiation device

Abstract

To provide an ultraviolet irradiation device which can irradiate an overall wafer surface with an ultraviolet ray so that an integrated amount of light of ultraviolet rays radiated to a wafer is constant.SOLUTION: An ultraviolet irradiation device 1 includes: a chuck table 10 which holds a wafer unit 100, having an ultraviolet curable protective tape 121 adhered to a disc-shaped wafer 110, on a holding surface 11 and rotates around a revolving shaft 13 perpendicular to the holding surface 11; and an ultraviolet light source unit 20 having a base 21 which faces the wafer unit 100 held by the chuck table 10 to cover a fan-shaped region 117, which spreads outward in the radial direction from the center 116 of the wafer 110, and a plurality of UV LEDs 22 arranged on the base 21. The plurality of UV LEDs 22 of the ultraviolet light source unit 20 are arranged on the base 21 correspondingly to a spiral locus starting from the center 116 of the wafer 110 such that the integrated amount of light of the ultraviolet rays radiated to the rotating wafer unit 100 is constant.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ultraviolet irradiation device. [Background technology]

[0002] In the manufacture of semiconductor device chips, the backside of a substrate on which devices are formed on its surface is ground to thin it, and then the substrate is separated into individual device chips by cutting, etc. During this process, protective tape is attached to the wafer to protect the devices during grinding and to hold the separated chips together so that they do not fall apart when separated.

[0003] Since it is desirable for the protective tape to be strongly fixed and have a reduced adhesive strength when peeled off, an ultraviolet-curing UV tape is sometimes used, which can control the adhesive strength by curing the adhesive layer with ultraviolet light. The UV tape is designed so that when the ultraviolet light irradiated by an ultraviolet light irradiation device such as that disclosed in Patent Document 1 reaches a predetermined cumulative light amount, the adhesive layer hardens and the adhesive strength becomes equal to or less than a predetermined level. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-329300 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when controlling the adhesive strength of a UV tape by irradiating ultraviolet light, it is necessary to irradiate the entire surface of the wafer with a certain cumulative light amount. However, for example, an ultraviolet irradiator that irradiates the entire surface of the wafer with ultraviolet light at the same time needs to be equipped with a light source in which many UV lamps, UV LEDs, and other UV lights are arranged, which is problematic in that the manufacturing cost is high. In addition, for example, an ultraviolet irradiator that scans a wafer with a rod-shaped light source in which UV lights are arranged in a straight line has a problem that it generates heat to a high temperature because, depending on the specifications of the UV lights, it is necessary to narrow the interval between the UV lights to achieve the cumulative light amount.

[0006] The present invention has been made in consideration of such problems, and its object is to provide an ultraviolet irradiation apparatus that can irradiate ultraviolet rays onto the entire surface of a wafer so that the integrated light amount of ultraviolet rays irradiated onto the wafer is constant. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the ultraviolet irradiation device of the present invention is an ultraviolet irradiation device that irradiates ultraviolet rays onto a wafer unit having an ultraviolet-curable protective tape attached to a disk-shaped wafer, and includes a chuck table that holds the wafer unit on a holding surface and rotates on a rotation axis perpendicular to the holding surface, an ultraviolet light source unit that faces the wafer unit held on the chuck table and includes a base that covers a sector-shaped area spreading radially outward from the center of the wafer, and a plurality of UVLEDs arranged on the base, the base is in a sector shape having a corner located on a rotation axis of the chuck table and an arc portion located radially outward from an outer edge of the chuck table, The UV LEDs of the ultraviolet light source are arranged on the base in accordance with a spiral trajectory starting from the center of the wafer so that the cumulative amount of ultraviolet light irradiated onto the rotating wafer unit is constant. and arranged such that the circumferential interval between adjacent ones along the spiral, centered on the corner, gradually narrows from the corner toward the arc portion. It is characterized by the above.

[0008] The present invention can irradiate the entire surface of a wafer with ultraviolet light so that the integrated light amount of the ultraviolet light irradiated onto the wafer is constant. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a wafer unit that is an irradiation target of an ultraviolet irradiation device according to an embodiment. [Diagram 2] FIG. 2 is a side view, partially in cross section, showing a schematic view of the ultraviolet irradiation device according to the embodiment. [Diagram 3] FIG. 3 is a plan view of the ultraviolet irradiation device shown in FIG. [Figure 4] FIG. 4 is a perspective view showing an example of an ultraviolet light source unit of the ultraviolet irradiation device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. Furthermore, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the gist of the present invention.

[0011] [Embodiment] An ultraviolet irradiation device 1 according to an embodiment of the present invention will be described with reference to the drawings. First, a configuration of a wafer unit 100 which is an object of irradiation by the ultraviolet irradiation device 1 according to the embodiment will be described. Fig. 1 is a perspective view showing an example of a wafer unit 100 which is an object of irradiation by the ultraviolet irradiation device 1 according to the embodiment.

[0012] 1, the wafer unit 100 includes a wafer 110, an annular frame 120, and a protective tape 121. The wafer 110 is a disk-shaped semiconductor wafer, an optical device wafer, or the like, with a substrate 111 made of silicon (Si), sapphire (Al2O3), gallium arsenide (GaAs), silicon carbide (SiC), or the like. The wafer 110 has a plurality of planned division lines 113 formed on a surface 112 of the substrate 111, and devices 114 formed in each region partitioned by the plurality of planned division lines 113 intersecting in a lattice pattern.

[0013] The devices 114 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), or MEMS (Micro Electro Mechanical Systems). A back surface 115 of the wafer 110 opposite to the front surface 112 on which the devices 114 are formed is ground to a finishing thickness by, for example, a grinding device. After being thinned, the wafer 110 is divided along the division lines 113 by, for example, cutting with a cutting blade or laser processing with a laser beam, and is singulated into individual device chips.

[0014] The annular frame 120 has an opening larger than the outer diameter of the wafer 110. The annular frame 120 is made of a material such as metal or resin. The outer periphery of the protective tape 121 is attached to the back surface side of the annular frame 120. The wafer 110 is positioned at a predetermined position in the opening of the annular frame 120, and the front surface 112 is attached to the front surface of the protective tape 121, thereby being fixed to the annular frame 120 and the protective tape 121.

[0015] The protective tape 121 is an ultraviolet-curing UV tape whose adhesive strength can be controlled by curing the adhesive layer with ultraviolet light. Note that UV stands for "ultraviolet." The protective tape 121 has an adhesive layer that is adhesive and hardens when irradiated with ultraviolet light, reducing its adhesive strength. The protective tape 121 has a base layer made of, for example, a synthetic resin, and an adhesive layer is laminated on at least one of the front and back surfaces of the base layer.

[0016] Next, the configuration of the ultraviolet irradiation device 1 according to the embodiment will be described. FIG. 2 is a side view showing a schematic partial cross section of the ultraviolet irradiation device 1 according to the embodiment. FIG. 3 is a plan view of the ultraviolet irradiation device 1 shown in FIG. 2. FIG. 4 is a perspective view showing an example of an ultraviolet light source unit 20 of the ultraviolet irradiation device 1 shown in FIG. 2. The ultraviolet irradiation device 1 is a device that irradiates ultraviolet rays onto a wafer unit 100 in which an ultraviolet-curable protective tape 121 is attached to a disk-shaped wafer 110. The ultraviolet irradiation device 1 has a chuck table 10 and an ultraviolet light source unit 20.

[0017] The chuck table 10 holds the back surface 115 side of the wafer 110 with a holding surface 11. The holding surface 11 is disk-shaped and made of porous ceramics or the like. In the embodiment, the holding surface 11 is a flat surface parallel to the horizontal direction. The holding surface 11 is connected to a vacuum suction source, for example, via a vacuum suction path. The chuck table 10 holds the wafer 110 placed on the holding surface 11 by suction. A plurality of clamps may be arranged around the chuck table 10 to clamp an annular frame 120 that supports the wafer 110.

[0018] The chuck table 10 is rotatable about a rotation axis 13 perpendicular to the holding surface 11 by a rotation unit 12. The rotation unit 12 rotates the chuck table 10 about the rotation axis 13 relative to the main body 2 of the ultraviolet irradiator 1. The wafer unit 100 is held such that the center 116 of the wafer 110 coincides with the rotation axis 13.

[0019] The ultraviolet light source unit 20 irradiates ultraviolet light onto the wafer unit 100 held on the holding surface 11 of the chuck table 10. The ultraviolet light source unit 20 is installed on a pillar 3 standing upright from the apparatus main body 2. The ultraviolet light source unit 20 includes a base 21, a plurality of UVLEDs 22, and a plurality of heat dissipation holes 23. It should be noted that LED stands for "Light Emitting Diode."

[0020] The base 21 has a plate shape in a substantially horizontal position and is supported by pillars 3 erected from the apparatus main body 2. The base 21 faces the wafer unit 100 held on the chuck table 10, and covers a sector-shaped area 117 that spreads radially outward from the center 116 of the wafer 110. In the embodiment, the base 21 has a sector shape with an angle 24 of about 90° in a plan view. The base 21 is supported by the pillars 3 with the angle 24 located at the center 116 of the wafer 110, i.e., on the rotation axis 13 of the chuck table 10, and the arc portion 25 located radially outward from the outer edge of the chuck table 10, in a plan view.

[0021] The UVLEDs 22 are disposed on the base 21. More specifically, the UVLEDs 22 are disposed on the lower surface side of the base 21 facing the chuck table 10 so as to irradiate the wafer 110 of the wafer unit 100 held on the chuck table 10 with ultraviolet light. The UVLEDs 22 are disposed on the base 21 in a plan view corresponding to a spiral trajectory starting from the center 116 of the wafer 110 so that the cumulative amount of ultraviolet light irradiated to the wafer unit 100 on the chuck table 10 rotated by the rotation unit 12 is constant. The UVLEDs 22 are disposed such that the interval 26 between adjacent ones along the above-mentioned spiral gradually narrows from the corner 24 toward the arc portion 25 so that the cumulative amount of ultraviolet light irradiated to the wafer unit 100 on the chuck table 10 rotated by the rotation unit 12 is constant.

[0022] The heat dissipation holes 23 are through holes formed in a portion of the base 21 where the UVLEDs 22 are not arranged. The heat dissipation holes 23 are holes for reducing the weight of the base 21 and dissipating heat generated by irradiation of ultraviolet rays by the UVLEDs 22 to the outside. In the embodiment, the multiple heat dissipation holes 23 are provided along the radial outside of the spiral trajectory of the UVLEDs 22. Note that a heat sink may be provided on the surface (upper surface) of the base 21 opposite to the surface (lower surface) on which the UVLEDs 22 are arranged. This can further improve the heat dissipation effect.

[0023] As described above, the ultraviolet irradiation device 1 according to the embodiment has an ultraviolet light source unit 20 including a base 21 that faces the wafer unit 100 held on the chuck table 10 and covers a sector-shaped region 117 that spreads radially outward from the center 116 of the wafer 110, and a plurality of UVLEDs 22 arranged on the base 21. That is, the plurality of UVLEDs 22 are arranged so as to irradiate ultraviolet light onto the sector-shaped region 117 that spreads radially outward from the center 116 of the wafer 110, and the entire surface of the wafer 110 is sequentially irradiated with ultraviolet light by the rotation of the wafer 110. This allows the entire surface of the wafer 110 to be efficiently irradiated with ultraviolet light even with a small number of UVLEDs 22.

[0024] Furthermore, the multiple UVLEDs 22 of the ultraviolet light source section 20 are arranged on the base 21 in correspondence with a spiral trajectory starting from the center 116 of the wafer 110 so that the cumulative amount of ultraviolet light irradiated to the rotating wafer unit 100 is constant. In this way, by arranging the UVLEDs 22 in a sector-shaped region while leaving a space 26 between the UVLEDs 22, it is possible to irradiate ultraviolet light with a similar cumulative amount of light even near the center 116 and near the outer periphery of the wafer 110, which have different peripheral speeds when the wafer 110 is rotated.

[0025] It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. [Explanation of symbols]

[0026] 1 Ultraviolet irradiation device 10 Chuck table 11 Holding surface 13 Rotation axis 20 Ultraviolet light source section 21 Foundation 22 UV LEDs 100 wafer units 110 wafers 116 Center 117 areas 121 Protective Tape

Claims

[Claim 1] An ultraviolet irradiation device that irradiates ultraviolet rays onto a wafer unit having a disk-shaped wafer with an ultraviolet-curable protective tape attached thereto, a chuck table that holds the wafer unit on a holding surface and rotates on a rotation axis perpendicular to the holding surface; an ultraviolet light source unit including a base that faces the wafer unit held on the chuck table and covers a sector-shaped area that spreads radially outward from the center of the wafer, and a plurality of UVLEDs that are arranged on the base; having the base is in a sector shape having a corner located on a rotation axis of the chuck table and an arc portion located radially outward from an outer edge of the chuck table, The multiple UVLEDs of the ultraviolet light source section are arranged on the base in correspondence with a spiral trajectory starting from the center of the wafer so that the cumulative amount of ultraviolet light irradiated to the rotating wafer unit is constant, and are arranged such that the circumferential distance between adjacent ones along the spiral, centered on the corner, gradually narrows from the corner toward the arc portion.

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