JP7584259B2 - Ultraviolet irradiation equipment - Google Patents

Description

The present invention relates to an ultraviolet irradiation device.

If oxygen is present in the irradiation space when the frame unit is irradiated with ultraviolet light, the irradiation efficiency is poor, so a structure is known in which a chamber is prepared to cover the frame unit and an inert gas (e.g., nitrogen) is supplied into the chamber (see, for example, Patent Document 1).

JP 2020-096177 A

However, the structure of Patent Document 1 had problems with the amount of inert gas supplied to the irradiation space and the supply time.

The present invention was made in consideration of these problems, and its purpose is to provide an ultraviolet irradiation device that can reduce the amount of inert gas supplied to the irradiation space and the supply time.

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 frame unit that supports a wafer via an adhesive tape at an opening of an annular frame, and is characterized in that it comprises a holding table having a holding surface that transmits ultraviolet rays and holds the adhesive tape side of the frame unit on the holding surface, an ultraviolet irradiation unit that is installed below the holding table and irradiates ultraviolet rays onto the adhesive tape, a lid whose outer periphery is placed on the annular frame and forms an enclosed space between the lid and the annular frame, and a drive unit that moves the lid and the holding table relatively closer to and farther apart, wherein the lid is spaced from the adhesive tape of the frame unit when the lower surface of the lid contacts the upper surface of the annular frame, forming the enclosed space between the lid, the adhesive tape of the frame unit, and the annular frame, and has an atmospheric vent hole and a gas supply hole that is connected to an inert gas supply source and supplies an inert gas between the lid and the frame unit.

The lid may have a recess on the surface facing the frame unit.

The lid may include a light meter.

The present invention can reduce the amount of inert gas supplied to the irradiation space and the supply time.

FIG. 1 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiating device according to the first embodiment. FIG. 2 is a perspective view of the lid of the ultraviolet irradiation device of FIG. 1 as seen from above. FIG. 3 is a diagram showing details of the air vent hole and roof member of the lid of FIG. FIG. 4 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiating device according to the second embodiment. FIG. 5 is a perspective view of the lid of the ultraviolet irradiation device of FIG. 4 as seen from below.

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 1]
An ultraviolet irradiation device 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation device 1 according to the first embodiment. FIG. 2 is a perspective view showing the lid 30 of the ultraviolet irradiation device 1 of FIG. 1 from above. FIG. 3 is a view showing details of the air vent hole 32 and the roof member 33 of the lid 30 of FIG. 2. The lid 30 of FIG. 1 is a cross-sectional view taken along line (I)-(I) in FIG. 2. FIG. 3 is a cross-sectional view taken along line (III)-(III) in FIG. 2. The ultraviolet irradiation device 1 according to the first embodiment includes a holding table 10, an ultraviolet irradiation unit 20, a lid 30, a drive unit 40, and a control unit 50, as shown in FIG. 1.

As shown in FIG. 1, the frame unit 110, which is the target of ultraviolet irradiation by the ultraviolet irradiation device 1 according to the first embodiment, has a wafer 100, an adhesive tape 105 attached to the rear surface of the rear side of the wafer 100, and an annular frame 106 attached to the outer edge of the adhesive tape 105. The annular frame 106 is a flat plate, for example made of stainless steel, with both sides formed flat, and an opening 107 is formed in the center. The frame unit 110 supports the wafer 100 via the adhesive tape 105 in the opening 107 of the annular frame 106. The wafer 100 is, for example, a disk-shaped semiconductor wafer or an optical device wafer made of silicon, sapphire, silicon carbide (SiC), gallium arsenide, or the like as a base material. In the first embodiment, the wafer 100 is irradiated with a laser beam along a plurality of planned division lines formed in a lattice shape on the front surface to form a modified layer, and is divided into chip-sized devices 103 starting from the formed modified layer. The present invention is not limited to this, and the wafer 100 may be divided into devices 103 by other processing steps.

The holding table 10 comprises a plate-shaped frame member 11 in which a circular recess 13 and a through hole 14 are formed, and a disk-shaped table plate 12 fitted into the recess 13. The frame member 11 is formed of a material that does not transmit ultraviolet light. The diameter of the circular through hole 14 in the frame member 11 is larger than the outer diameter of the wafer 100 in the frame unit 110. The table plate 12 is formed of a material that transmits ultraviolet light. The upper surface of the table plate 12 is a holding surface 15 on which the adhesive tape 105 side of the frame unit 110 is placed and which holds the adhesive tape 105 side of the frame unit 110. The holding surface 15 and the upper surface of the frame member 11 are arranged on the same plane and are formed parallel to a horizontal plane.

The ultraviolet irradiation unit 20 is installed below the table plate 12 of the holding table 10 and includes a plurality of UVLEDs (UltraViolet Light Emitting Diodes) 21 arranged in a plane over an area approximately equal to the through holes 14 in a planar view. The ultraviolet irradiation unit 20 irradiates ultraviolet light onto the adhesive tape 105 of the frame unit 110 on the holding surface 15 via the table plate 12 using the UVLEDs 21, thereby reducing the adhesiveness of the adhesive tape 105.

As shown in Figs. 1 and 2, the lid 30 has a lid body 31, an air vent hole 32, a roof member 33, a gas supply hole 34, and a light meter 35. The lid body 31 is a circular flat plate made of a material that does not transmit ultraviolet light. The diameter of the lid body 31 is at least larger than the inner diameter of the annular frame 106 of the frame unit 110, and in the first embodiment, is also larger than the outer diameter of the annular frame 106 of the frame unit 110. In the first embodiment, the lower surface 36 of the lid body 31 facing the frame unit 110 is formed flat.

When the lid body 31 of the lid 30 is placed on the annular frame 106 of the frame unit 110, the surface 36 of the lid body 31 comes into contact with the upper surface of the annular frame 106 over the entire circumference, and the surface 36 of the lid body 31 approaches the adhesive tape 105 of the frame unit 110, forming an enclosed space 60 with a narrow width in the thickness direction between the surface 36 of the lid body 31 and the adhesive tape 105 and annular frame 106 of the frame unit 110.

As shown in FIG. 1, the air vent hole 32 is formed penetrating the thickness direction of the lid body 31 at a position on the inner side of the area facing the annular frame 106. In the first embodiment, the air vent hole 32 is located on the outer side of the area of the lid body 31 facing the wafer 100 (device 103) when the lid body 31 is placed on the annular frame 106 as shown in FIG. 1. In the first embodiment, the air vent hole 32 is formed at multiple locations (four locations at a phase angle of 90° in the example shown in FIG. 2) at equal intervals along the circumferential direction of the lid body 31 as shown in FIG. 2.

When an inert gas such as nitrogen (N ₂ ) is supplied from the gas supply hole 34 into the sealed space 60, the air vent hole 32 becomes an exhaust hole that exhausts air containing active gas such as oxygen (O ₂ ) in the sealed space 60 upward to the outside of the sealed space 60. Here, the inert gas is a gas that does not sufficiently reduce the irradiation efficiency of ultraviolet light. In the first embodiment, nitrogen (N ₂ ) is used as the inert gas, but the present invention is not limited to this. Also, the active gas is a gas that may reduce the irradiation efficiency of ultraviolet light. In the first embodiment, the active gas is oxygen (O ₂ ).

As shown in FIG. 2, the roof members 33 are disposed for each atmospheric vent hole 32. As shown in FIG. 3, the roof members 33 are disposed spaced upward from the atmospheric vent holes 32 so as to cover the upper part of the atmospheric vent holes 32. The roof members 33 are formed of a material that does not transmit ultraviolet light. The roof members 33 form an exhaust path so that air exhausted upward from the atmospheric vent holes 32 is exhausted from between the roof members 33 and the atmospheric vent holes 32 along the radial direction of the lid body 31.

In the first embodiment, as shown in FIG. 2, the gas supply hole 34 is formed penetrating the center of the lid body 31 in the thickness direction. As shown in FIG. 1, the upper side of the gas supply hole 34 is connected to the inert gas supply source 39, and the inert gas supplied from the inert gas supply source 39 is supplied from above into the sealed space 60. When the gas supply hole 34 supplies the inert gas into the sealed space 60, a gas flow from the gas supply hole 34 toward the atmospheric vent hole 32 is formed in the sealed space 60, that is, a gas flow along the radial direction from the center of the lid body 31 toward the outer periphery.

The number and positions of the atmospheric vent holes 32 and the gas supply holes 34 are preferably formed so that a gas flow is formed in a fixed direction from the gas supply holes 34 toward the atmospheric vent holes 32 as in the form shown in FIG. 2 of the first embodiment, but the present invention is not limited to this form. Other preferred forms include, for example, a form in which the number and positional relationship between the atmospheric vent holes 32 and the gas supply holes 34 is reversed to the form shown in FIG. 2, the atmospheric vent holes 32 are formed on the center side, and the gas supply holes 34 are formed on the outer periphery side, and when inert gas is supplied into the sealed space 60 from the gas supply holes 34, a gas flow is formed along the radial direction from the outer periphery of the lid body 31 toward the center.

The illuminometer 35 is disposed facing downward in an area of the lid body 31 facing the wafer 100 (device 103) when the lid body 31 is placed on the annular frame 106. The illuminometer 35 measures the actual illuminance of the ultraviolet light irradiated from the ultraviolet irradiation unit 20 toward the adhesive tape 105.

The drive unit 40 is attached above the lid body 31 of the lid 30 and supports the lid body 31 of the lid 30 from above. The drive unit 40 raises and lowers the lid body 31 of the lid 30, thereby moving the lid body 31 of the lid 30 closer to and farther away from the holding table 10 in the vertical direction.

The control unit 50 controls each component of the ultraviolet irradiation device 1 and causes the ultraviolet irradiation device 1 to perform each operation related to the ultraviolet irradiation process for the frame unit 110. In the first embodiment, the control unit 50 includes a computer system. The control unit 50 has an arithmetic processing device having a microprocessor such as a CPU (Central Processing Unit), a storage device having a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input/output interface device. The arithmetic processing device of the control unit 50 performs arithmetic processing according to a computer program stored in the storage device of the control unit 50, and outputs a control signal for controlling the ultraviolet irradiation device 1 to each component of the ultraviolet irradiation device 1 via the input/output interface device of the control unit 50.

Next, this specification describes an example of the operation process of the ultraviolet irradiation device 1 according to the first embodiment. When the frame unit 110 is placed on the holding surface 15 of the table plate 12 of the holding table 10, the control unit 50 uses the drive unit 40 to lower the lid body 31 of the lid 30 to approach the holding table 10, place the lid body 31 on the annular frame 106 in an overlapping manner, and contact the outer periphery of the surface 36 of the lid body 31 with the upper surface of the annular frame 106 over the entire circumference to form a sealed space 60. After forming the sealed space 60, the control unit 50 controls the inert gas supply source 39 to supply inert gas from the gas supply hole 34 into the sealed space 60, and discharges the active gas remaining in the sealed space 60 from the atmosphere opening hole 32 so as to push it out with the supplied inert gas, thereby filling the sealed space 60 with inert gas.

After filling the sealed space 60 with inert gas, the control unit 50 causes the ultraviolet irradiation unit 20 to irradiate ultraviolet light onto the frame unit 110 on the holding surface 15 within the sealed space 60 filled with inert gas. Here, the control unit 50 controls the voltage applied to each UVLED 21 of the ultraviolet irradiation unit 20 to control the actual illuminance measured by the illuminometer 35, thereby controlling the actual illuminance of the ultraviolet light irradiated by the ultraviolet irradiation unit 20 onto the adhesive tape 105 of the frame unit 110.

The ultraviolet irradiation device 1 according to the first embodiment having the above-mentioned configuration contacts the lower surface 36 of the lid body 31 of the lid 30 with the upper surface of the annular frame 106 of the frame unit 110 over the entire circumference of the upper surface of the annular frame 106, forming an enclosed space 60 with a narrow width in the thickness direction between the lid body 31 and the adhesive tape 105 and annular frame 106 of the frame unit 110, and replacing the air in this enclosed space 60 with an inert gas, making this enclosed space 60 an ultraviolet irradiation space. In the ultraviolet irradiation device 1 according to the first embodiment, the enclosed space 60 that becomes the ultraviolet irradiation space has a significantly smaller volume than the irradiation space formed by the conventional chamber, so that the amount and supply time of the inert gas supplied to the irradiation space can be significantly reduced compared to the case where the irradiation space is formed by the conventional chamber, and the overall device can be made smaller than the structure having the conventional chamber.

In addition, the ultraviolet irradiation device 1 according to embodiment 1 forms a sealed space 60 that is narrow in the thickness direction, and the gas supply hole 34 for supplying the inert gas is formed in the center of the lid 30, and the air vent hole 32 for discharging the air is formed in a position slightly inside the annular frame 106 of the lid 30. Therefore, when the inert gas is supplied, a gas flow can be formed in a fixed direction from the center of the lid 30 toward the outer periphery, and the air in the sealed space 60 can be efficiently replaced with the inert gas.

In addition, in the ultraviolet irradiation device 1 according to embodiment 1, the illuminometer 35 is provided close to the adhesive tape 105 of the frame unit 110, so that the actual illuminance of the ultraviolet light irradiated onto the adhesive tape 105 of the frame unit 110 can be precisely controlled.

In addition, the ultraviolet irradiation device 1 according to the first embodiment has a roof member 33 that covers the upper part of the atmospheric vent 32, so that the upward leakage of ultraviolet light from the atmospheric vent 32 can be reduced.

[Embodiment 2]
An ultraviolet irradiation device 1-2 according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 4 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation device 1-2 according to the second embodiment. Fig. 5 is a perspective view of the cover 30-2 of the ultraviolet irradiation device 1-2 in Fig. 4, seen from below. In Figs. 4 and 5, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The ultraviolet irradiation device 1-2 according to the second embodiment includes a lid 30-2 instead of the lid 30 of the first embodiment. In addition to the components of the lid 30, the lid 30-2 has an outer peripheral surface 37 and a recess 38, as shown in Figs. 4 and 5. The outer peripheral surface 37 is an annular flat surface corresponding to the outer peripheral portion of the surface 36 of the lid body 31 of the first embodiment, and surrounds the outer periphery of the recess 38. The recess 38 is formed in the center of the surface 36 side of the lid body 31 of the first embodiment, recessed from the outer peripheral surface 37. The diameter of the recess 38 is larger than the outer diameter of the wafer 100 of the frame unit 110 and smaller than the outer diameter of the annular frame 106 of the frame unit 110. In the second embodiment, the diameter of the recess 38 is equal to the inner diameter of the annular frame 106 of the frame unit 110.

When the lid body 31 of the lid 30-2 is placed on the annular frame 106 of the frame unit 110, the outer peripheral surface 37 comes into contact with the upper surface of the annular frame 106 of the frame unit 110 over the entire circumference of the upper surface of the annular frame 106, forming an enclosed space 60-2 with a narrow width in the thickness direction between the outer peripheral surface 37 and recess 38 of the lid body 31 and the adhesive tape 105 and annular frame 106 of the frame unit 110.

The ultraviolet irradiation device 1-2 according to the second embodiment, which has the above-mentioned configuration, has a recess 38 formed on the lower surface 36 of the lid body 31 that faces the frame unit 110. In addition to achieving the same effects as those of the first embodiment, the device can reduce the risk of the lid body 31 and the adhesive tape 105 coming too close to each other and causing the adhesive tape 105 to stick to the lower surface 36 of the lid body 31.

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, 1-2 UV irradiation device 10 Holding table 15 Holding surface 20 UV irradiation unit 30, 30-2 Lid 32 Atmospheric release hole 34 Gas supply hole 35 Illuminometer 38 Recess 39 Inert gas supply source 40 Drive unit 60, 60-2 Sealed space 100 Wafer 105 Adhesive tape 106 Annular frame 110 Frame unit

Claims (3)

An ultraviolet irradiation device that irradiates ultraviolet rays onto a frame unit that supports a wafer through an adhesive tape in an opening of an annular frame,
a holding table having a holding surface that transmits ultraviolet light and holds the adhesive tape side of the frame unit on the holding surface;
an ultraviolet irradiation unit that is installed below the holding table and irradiates the adhesive tape with ultraviolet light;
a lid having an outer periphery placed on the annular frame and forming a sealed space between the lid and the annular frame;
a drive unit for moving the lid and the holding table relatively close to and away from each other;
The lid is
when a lower surface of the lid contacts an upper surface of the annular frame, the lid is spaced from the adhesive tape of the frame unit, and the sealed space is formed between the lid, the adhesive tape of the frame unit, and the annular frame;
An air vent hole;
a gas supply hole connected to an inert gas supply source and supplying an inert gas between the lid and the frame unit;
An ultraviolet irradiation device comprising: The ultraviolet irradiation device according to claim 1, characterized in that the lid has a recess on the surface facing the frame unit. The ultraviolet irradiation device according to claim 1 or 2, characterized in that the lid has a luminometer.

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