JP7630262B2 - Ultraviolet irradiation equipment - Google Patents

Description

The present invention relates to an ultraviolet irradiation device.

In the manufacture of semiconductor device chips, the backside of a substrate on which devices are formed is ground to thin it, and then it is separated into individual device chips by cutting or other methods. 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.

Since it is desirable for protective tape to be strongly fixed and have a reduced adhesive strength when peeled off, ultraviolet-curing UV tape is sometimes used, which can control the adhesive strength by hardening the adhesive layer with ultraviolet light. 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.

JP 2007-329300 A

When controlling the adhesive strength of a UV tape by irradiating it with ultraviolet light, it is necessary to irradiate the entire surface of the wafer with a constant cumulative light amount. However, for example, an ultraviolet irradiation device that simultaneously irradiates the entire surface of the wafer with ultraviolet light needs to be equipped with a light source in which many UV lamps, UV LEDs, or other UV lights are arranged, which raises the issue of high manufacturing costs. Also, for example, an ultraviolet irradiation device that scans a wafer with a rod-shaped light source in which UV lights are arranged in a straight line has the issue that, depending on the specifications of the UV lights, the spacing between the UV lights needs to be narrowed to achieve the cumulative light amount, which can result in high heat generation.

The present invention was made in consideration of these problems, and its purpose is to provide an ultraviolet irradiation device that can irradiate ultraviolet rays onto the entire surface of a wafer so that the cumulative amount of ultraviolet light irradiated onto the wafer is constant.

In order to solve the above-mentioned problems and achieve the object, an 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 with a holding surface and rotates on a rotation axis perpendicular to the holding surface, a base that faces the wafer unit held on the chuck table and covers a sector-shaped area spreading radially outward from the center of the wafer, and an ultraviolet light source unit including a plurality of UVLEDs arranged on the base, the base being sector-shaped having a corner located on the rotation axis of the chuck table and an arc portion located radially outward from the outer edge of the chuck table, the plurality of UVLEDs of the ultraviolet light source unit being arranged on the base in correspondence with a spiral trajectory starting from the center of the wafer so that the integrated light amount of ultraviolet rays irradiated onto the rotating wafer unit is constant , and being arranged such that the circumferential distance between adjacent ones along the spiral, centered on the corner, gradually narrows as it moves from the corner toward the arc portion .

The present invention can irradiate the entire surface of a wafer with ultraviolet light so that the cumulative amount of ultraviolet light irradiated onto the wafer is constant.

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. FIG. 2 is a side view, partially in cross section, showing a schematic view of the ultraviolet irradiation device according to the embodiment. FIG. 3 is a plan view of the ultraviolet irradiation device shown in FIG. FIG. 4 is a perspective view showing an example of an ultraviolet light source unit of the ultraviolet irradiation device shown in FIG.

The following describes in detail the form (embodiment) for carrying out the present invention with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. 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 combined as appropriate. Various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

[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 that 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 that is an object of irradiation by the ultraviolet irradiation device 1 according to the embodiment.

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 silicon (Si), sapphire (Al ₂ O ₃ ), gallium arsenide (GaAs), silicon carbide (SiC), or the like, serving as a substrate 111. 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.

The devices 114 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integration), image sensors such as CCDs (Charge Coupled Devices) or CMOSs (Complementary Metal Oxide Semiconductors), or MEMS (Micro Electro Mechanical Systems). The back surface 115 of the wafer 110, which is opposite 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 intended 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.

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 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 surface 112 is attached to the surface of the protective tape 121, thereby fixing the wafer 110 to the annular frame 120 and the protective tape 121.

The protective tape 121 is an ultraviolet-curing UV tape that can control the adhesive strength 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.

Next, the configuration of the ultraviolet irradiation device 1 according to the embodiment will be described. FIG. 2 is a side view showing the ultraviolet irradiation device 1 according to the embodiment, in a schematic partial cross section. 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 light 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.

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.

The chuck table 10 can be rotated by the rotation unit 12 around a rotation axis 13 perpendicular to the holding surface 11. The rotation unit 12 rotates the chuck table 10 around the rotation axis 13 relative to the main body 2 of the ultraviolet irradiation device 1. The wafer unit 100 is held so that the center 116 of the wafer 110 coincides with the rotation axis 13.

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 device main body 2. The ultraviolet light source unit 20 includes a base 21, a number of UVLEDs 22, and a number of heat dissipation holes 23. Note that LED stands for "Light Emitting Diode."

The base 21 is a plate-like member in a substantially horizontal position supported by pillars 3 erected from the main body 2 of the apparatus. 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 is sector-shaped with an angle 24 of approximately 90° in plan view. In 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.

The UVLEDs 22 are arranged on the base 21. More specifically, the UVLEDs 22 are arranged on the underside of the base 21 facing the chuck table 10 so as to irradiate ultraviolet light onto the wafer 110 of the wafer unit 100 held on the chuck table 10. The UVLEDs 22 are arranged 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 onto the wafer unit 100 on the chuck table 10 rotated by the rotation unit 12 is constant. The UVLEDs 22 are arranged so 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 onto the wafer unit 100 on the chuck table 10 rotated by the rotation unit 12 is constant.

The heat dissipation holes 23 are through holes formed in the 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 the 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.

As described above, the ultraviolet irradiation device 1 according to the embodiment has an ultraviolet light source unit 20 that faces the wafer unit 100 held on the chuck table 10 and includes a base 21 that covers a sector-shaped area 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 that they can irradiate ultraviolet light onto the sector-shaped area 117 that spreads radially outward from the center 116 of the wafer 110, and as the wafer 110 rotates, the entire surface of the wafer 110 is sequentially irradiated with ultraviolet light. This allows ultraviolet light to be efficiently irradiated onto the entire surface of the wafer 110 even with a small number of UVLEDs 22.

The UVLEDs 22 of the ultraviolet light source unit 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 the outer periphery of the wafer 110, which have different peripheral speeds when the wafer 110 is rotated.

The present invention is not limited to the above embodiment. In other words, the present invention can be implemented in various modifications without departing from the gist of the invention.

REFERENCE SIGNS LIST 1 Ultraviolet ray irradiation device 10 Chuck table 11 Holding surface 13 Rotation shaft 20 Ultraviolet ray light source unit 21 Base 22 UVLED
100 Wafer unit 110 Wafer 116 Center 117 Area 121 Protective tape

Claims (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 extending radially outward from the center of the wafer, and a plurality of UVLEDs 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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