The present invention relates to a UV irradiation apparatus and a UV irradiation method, and more particularly to a UV irradiation apparatus and a UV irradiation method using a light emitting diode.
In a processing apparatus of a semiconductor wafer (hereinafter, simply referred to as “wafer”), processings such as sticking a protective tape onto a wafer for backgrinding, and sticking a dicing tape onto a wafer for individualing it into multiple chips are performed. For a tape to be used for the above processings, a UV curable type is adopted as its adhesive, so that peeling can be easily performed without breaking the wafer, by curing the adhesive to weaken its adhesion by a UV irradiation apparatus after the above processings.
As for the above-described UV irradiation apparatus, for example, an apparatus arranged with a lamp case in a position corresponding to a wafer surface, and arranged with a high-pressure mercury lamp, a metal halide lamp, or the like, inside the lamp case, is known (Patent Document 1).
And, as a luminous source for irradiation with UV rays, a UV irradiation apparatus using a light emitting diode is suggested from the applicant of this application (Patent Document 2).
Patent Document 1: Japanese Patent Application Laid-Open No. 9-162141
Patent Document 2: Japanese Patent Application Laid-Open No. 2006-40944
However, since the UV irradiation apparatus disclosed in Patent Document 1 is arranged to use the high-pressure mercury lamp as a luminous source, it has disadvantages that a high-voltage transformer is required, therefore equipment-size becomes larger, and electric power consumption becomes higher. Additionally, it requires frequent maintenance because of short life of the lamps, and it takes a long time until meeting the UV irradiation condition, so-called rise time, and therefore the lamp needs to be continuously turned ON during the operation time, that causes very high electric power consumption. Further, since irradiation control in accordance with the plane area of an irradiation receiving body cannot be performed, waste of electric power consumption is unavoidable. Moreover, since mercury is used for the lamp, an environmental problem regarding disposal thereof needs to be considered.
In these points, since Patent Document 2 has an arrangement in which the light emitting diode is adopted as its luminous source, downsizing of the apparatus as well as easiness of maintenance check, operability and power saving of UV irradiation can be remarkably achieved.
However, in the arrangement using the light emitting diode, a problem newly occurred that a UV curable-type adhesive could not be cured in some cases.
Many UV curable-type adhesives are designed that their initiators begin light curing at approximately 365 nm of wavelength. In contrast, initiators for UV curing have many types and some begin the reaction at other than 365 nm of wavelength. An emission spectrum of the high-pressure mercury lamp has, as shown in
The present invention has been made in view of the above-described properties of a high-pressure mercury lamp and properties of a light emitting diode, in order to solve the problems in using the light emitting diode, based on knowledge and finding through various experiments; and an object is to provide a UV irradiation apparatus and a UV irradiation method while maintaining advantages in using the light emitting diode, while preventing occurrence of an uncured region in a UV curable-type adhesive.
In order to achieve the above objects, the present invention adopts such an arrangement that a UV irradiation apparatus arranged with a UV luminous body in a position corresponding to an irradiation receiving body, wherein
the UV luminous body comprises multiple types of UV light emitting diodes having different peak wavelengths.
According to the present invention, such an arrangement may be adopted that includes a base plate which is arranged substantially parallel to the irradiation receiving body, and is relatively movable with respect to the irradiation receiving body while maintaining the substantially parallel state; wherein
the light emitting diodes are supported by the base plate, and are arranged along the straight line substantially perpendicular to the relative movement direction at intervals of substantially equal spaces, and the rows are multiply provided along the relative movement direction; and
the peak wavelengths of the light emitting diodes in each row are set to be substantially the same, while the peak wavelengths in the adjacent rows are set to be not necessarily the same.
And, the light emitting diodes in the adjacent rows are preferably arranged to be positioned in between the adjacent light emitting diodes in each row viewing from the relative movement direction.
Also, such an arrangement maybe adopted that the light emitting diodes are provided to be attachable and detachable to and from the base plate.
Additionally, the light emitting diodes may be unitized respectively with two or more pieces in, and may be provided to be attachable and detachable to and from the base plate based on the respective units.
Further, such an arrangement may be adopted that the light emitting diodes are provided so that the luminous region can be controlled in accordance with plane area of the irradiation receiving body.
Furthermore, illuminance sensors may be arranged at intervals of equal spaces along the direction substantially perpendicular to the relative movement direction, on a table which supports the irradiation receiving body.
Still further, such an arrangement may be adopted that irradiating capacity of the light emitting diodes with respect to each unit being unitized with two or more pieces or with respect to each piece is detected by a current value and/or a voltage level.
The present invention adopts such an arrangement that a UV irradiation method in which multiple UV light emitting diodes are arranged in a position corresponding to an irradiation receiving body so as to irradiate with UV rays from the UV light emitting diodes onto the irradiation receiving body, wherein
multiple types of UV rays having different peak wavelengths are irradiated onto a UV irradiation region in the irradiation receiving body.
In the above method, the irradiation receiving body may be a sheet stuck to a semiconductor wafer through a UV curable adhesive.
According to the present invention, since the UV irradiation apparatus includes multiple types of light emitting diodes having different peak wavelengths, even when UV curable-type adhesives different in properties of the initiators are used, UV rays having different wavelengths effect efficiently and UV curing over the whole region can be achieved. And, since the light emitting diodes are adopted as the luminous source, large-scaled equipment such as a transformer in the case of adopting a conventional lamp such as a mercury lamp becomes needless, whereby downsizing of equipment can be achieved. Additionally, when the light emitting diodes are arranged to be attachable and detachable to and from the base plate, maintenance by partial replacement can be easily achieved, and thereby allowing the burden of cost to be kept to a minimum. Further, when the UV luminous region is arranged to be controllable, product life of the light emitting diodes can be secured over a long period of time while electric power consumption can be lowered. Also, since a rise time like that of the high-pressure mercury lamp is not necessary, the light emitting diodes can be turned ON just before performing UV irradiation and can be turned OFF just after the end of the irradiation, therefore large amount of energy saving can be achieved compared to the high-pressure mercury lamp which is required to be continuously turned ON. Still further, when the illuminance sensors are provided, performance of the light emitting diodes can be assuredly evaluated, whereby insufficient UV irradiation can be avoided. Moreover, by controlling the current value and/or the voltage level using an ammeter and/or a voltmeter, a state of running out of a light emitting diode can be detected, whereby UV irradiation failure can be prevented.
10 UV IRRADIATION APPARATUS
11 WAFER SUPPORTING PORTION
12 UV IRRADIATING PORTION
17 ILLUMINANCE SENSOR
21 LIGHT EMITTING DIODE
W SEMICONDUCTOR WAFER (IRRADIATION RECEIVING BODY)
Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
The wafer supporting portion 11 includes a guide 15 which extends substantially parallel to the wafer W; a table 16 which is movably provided along the guide 15 and is formed of substantially a rectangular shape in plane view; and multiple illuminance sensors 17 which are arranged on the table 16 at intervals of equal spaces along the direction perpendicular to the front aspect of
As shown in
In the embodiment, the light emitting diodes 21 having substantially the same peak wavelength are adopted in the same row, so that the peak wavelengths are set to be different with respect to each row. To clarify the relationship, as shown in
In the above arrangement, by relatively moving the wafer supporting portion 11 and the UV irradiating portion 12 in the state that the light emitting diodes 21 emit UV rays, the UV curable-type adhesive of the adhesive layer 18 can be cured. In this regard, even when an initiator having a different value from a design value is in the adhesive layer 18, the light emitting diodes 21 having different peak wavelengths effect so as to complement to each other, whereby a proportion of a cured region in the adhesive layer 18 can be increased.
The light emitting diodes 21 are evaluated by the illuminance sensors 17 each time the wafer W is irradiated with UV rays, therefore, whenever a lowered illuminance is detected, voltage with respect to each unit being unitized with one or more than one piece is raised, so that necessary illuminance can be secured. Also, even when the voltage reaches to the upper limit and an insufficient illuminance is detected, UV irradiation can be performed constantly in a steady performance by replacing with respect to each unit being unitized with one or more than one piece.
Thus, according to the embodiment as described above, a UV irradiation apparatus and a UV irradiation method having non-conventionally excellent functions and effects can be provided, in which possible occurrence of conventional disadvantages such as occurrence of an uncured region when using the UV light emitting diodes 21 can be prevented.
The best arrangement, method and the like for carrying out the present invention have been disclosed so far. However, the present invention is not limited to the above.
That is, the present invention has been illustrated and described mainly about a specific embodiment. However, it is possible for those skilled in the art to add various modifications, if necessary, to the above-described embodiment with respect to the shape, position and/or disposition without departing from the technical spirit and the range of the object of the present invention.
For example, as shown in
This control can be achieved by inputting address data of each light emitting diode 21 or each unit, and a speed of the above-described relative movement into a control device (not shown in the figure), in advance. In the example of
And, as shown in
Also, the current value and/or voltage level with respect to each unit being unitized with two or more pieces may be measured to detect whether the light emitting diodes 21 are emitting light. An arrangement of measuring the current value and/or voltage level with respect to each one piece may obviously be adopted.
Additionally, in the present invention, the irradiation receiving body is not limited to a semiconductor wafer, and there is no restriction to be applied to other materials as long as the subject needs a UV irradiation reaction without producing any unirradiated region.
Further, although the light emitting diodes 21 are arranged to have substantially the same peak wavelength with respect to each row in the embodiment, the light emitting diodes 21 having different peak wavelengths may be arranged in a random manner regardless of the rows. That means, it is enough for the present invention as long as multiple types of light emitting diodes are adopted, instead of using only one type of light emitting diodes having a specific peak wavelength. The numbers, rows, and arrangements are not limited to the illustrated arrangement examples.
Optionally, although the arrangement in which the relative movement is performed by moving of the table 16 which supports the wafer W with respect to the base plate 20 which supports the light emitting diodes 21 has been illustrated, it may be arranged by moving of the base plate 20 side through a suitable guide mechanism while the table 16 is fixed, or may be arranged by moving of both of the table 16 and the base plate 20.
Still further, at the time of UV irradiation, inside of the chamber 13 surrounding the wafer supporting portion 11 and the UV irradiating portion 12 may be filled with nitrogen gas or may be decompressed so as to prevent UV cure inhibition by oxygen.
Number | Date | Country | Kind |
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2006-326720 | Dec 2006 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2007/071026 | 10/29/2007 | WO | 00 | 5/6/2009 |