Light irradiation device

Abstract

To provide an inexpensive light irradiation device with a simple configuration, having a function for dispersing white light by creating time differences corresponding to a plurality of wavelengths and radiating it.SOLUTION: A light irradiation device 1A for dispersing white light L0 into multiple wavelengths and radiating it, is constituted by including: a white light source 11; a diffraction grating 13 for dispersing the white light L0 emitted by the white light source 11; and light selection means for selecting light of a specific wavelength from light with a plurality of wavelengths dispersed by the diffraction grating 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light irradiation device that splits white light into a plurality of wavelengths and irradiates the light. [Background technology]

[0002] Wafers have a number of devices, such as ICs and LSIs, formed on their surface, separated by planned dividing lines. The back surface is ground to the desired thickness, and then the wafer is divided into individual device chips using a dicing machine or laser processing machine. These chips are then used in electrical devices such as mobile phones and personal computers.

[0003] The laser processing device positions the focal point of a laser beam having a wavelength that is transparent to the wafer inside the planned dividing lines and irradiates the laser beam, forming a modified layer along the planned dividing lines (see, for example, Patent Document 1).

[0004] Furthermore, the present applicant has proposed a technique for measuring the thickness of a wafer in order to accurately position the focal point of a laser beam inside the wafer (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3408805 [Patent Document 2] Japanese Patent Application Publication No. 2020-106374 Summary of the Invention [Problem to be solved by the invention]

[0006] To implement the technology described in Patent Document 2, a spectroscopic means is required to split white light into multiple wavelengths by creating a time difference. Conventional light irradiation devices equipped with spectroscopic means require a complex configuration to split the light by creating a time difference, which results in a problem that the thickness measurement device becomes expensive.

[0007] The present invention has been made in consideration of the above facts, and its main technical object is to provide a simple and inexpensive light irradiation device that disperses white light into multiple wavelengths with time differences and irradiates the light. [Means for solving the problem]

[0008] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a light irradiation device that splits white light into a plurality of wavelengths and irradiates the split white light, the light irradiation device including a white light source, a diffraction grating that splits the white light emitted by the white light source, and a light selecting means that selects light of a specific wavelength from the light of the plurality of wavelengths split by the diffraction grating. The light selecting means is a means for selecting light of a specific wavelength from light of a plurality of wavelengths dispersed by the diffraction grating by passing it through, and includes a first focusing mirror that reflects light of a plurality of wavelengths dispersed by the diffraction grating, a second focusing mirror that has the same focal length as the first focusing mirror and is disposed in a position that is point-symmetrical with respect to the focal point, an optical path conversion mirror that is positioned at the focal point of the second focusing mirror and changes the optical path, and a means for selecting and passing light of a plurality of wavelengths whose optical path has been converted by the optical path conversion mirror. A light irradiation device is provided.

[0009] The light It is preferable that a third focusing mirror is provided after the optical path conversion mirror, and the focal point of the third focusing mirror is positioned at the means for selecting and passing light of a plurality of wavelengths whose optical paths have been converted by the optical path conversion mirror. It is also preferable that the means for selecting and passing light of a plurality of wavelengths whose optical paths have been converted by the optical path conversion mirror is a pinhole mask. The optical path conversion mirror preferably includes any one of a galvanometer scanner, a resonant scanner, and a polygon mirror. The white light source can be selected from any one of an SLD light source, an ASE light source, an LED light source, a supercontinuum light source, a halogen light source, a xenon light source, a mercury light source, and a metal halide light source. [Effects of the Invention]

[0010] The light irradiation device of the present invention is a light irradiation device that splits white light into a plurality of wavelengths and irradiates the split light, and includes a white light source, a diffraction grating that splits the white light emitted by the white light source, and a light selection means that selects light of a specific wavelength from the light of the plurality of wavelengths split by the diffraction grating. The light selecting means is a means for selecting light of a specific wavelength from light of a plurality of wavelengths dispersed by the diffraction grating by passing it through, and includes a first focusing mirror that reflects light of a plurality of wavelengths dispersed by the diffraction grating, a second focusing mirror that has the same focal length as the first focusing mirror and is disposed in a position that is point-symmetrical with respect to the focal point, an optical path conversion mirror that is positioned at the focal point of the second focusing mirror and changes the optical path, and a means for selecting and passing light of a plurality of wavelengths whose optical path has been converted by the optical path conversion mirror. This provides a light irradiation device that is simple in configuration and inexpensive. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 10 is a conceptual diagram showing an optical system of a light irradiation device according to a reference example. [Figure 2] 1 is a conceptual diagram illustrating an optical system of a light irradiation device according to a first embodiment. [Figure 3] FIG. 10 is a conceptual diagram showing an optical system of a light irradiation device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes a light irradiation device constructed based on the present invention. Reference examples and The light irradiation device of the present invention can be configured in various ways. First, referring to FIG. Reference example The light irradiation device 1A configured as above will be described.

[0013] The light irradiation device 1A shown in FIG. 1 is a light irradiation device that splits white light into a plurality of wavelengths and irradiates the split light, and includes at least a white light source 11, a diffraction grating 13 that splits the white light L0 emitted by the white light source 11, and a light selection means that selects light of a specific wavelength from the light of the plurality of wavelengths split by the diffraction grating 13, for example, blue light Lb, green light Lg, and red light lr.

[0014] Book Reference example The white light source 11 is a light source that emits light L0 that is a substantially uniform mixture of light having a wavelength called visible light, for example, 400 nm to 800 nm, and is preferably any one of an SLD light source, an ASE light source, an LED light source, a supercontinuum light source, a halogen light source, a xenon light source, a mercury light source, and a metal halide light source. The white light L0 emitted from the white light source 11 is adjusted to be parallel light.

[0015] The light selecting means disposed in the light irradiation device 1A shown in Fig. 1 is composed of, for example, a pinhole mask 14 having a pinhole H, and angle adjusting means 12 that changes the angle of the diffraction grating 13 in the direction indicated by arrow R1 to adjust the irradiation direction of the light of multiple wavelengths (blue light Lb, green light Lg, and red light lr) dispersed by the diffraction grating 13. The angle adjusting means 12 is an electric motor, and is connected to and controlled by control means 100 that functions as a control driver. The angle adjusting means 12 is operated based on an instruction signal from the control means 100, and the angle of the diffraction grating 13 is changed in the direction indicated by arrow R1, as shown in Fig. 1, thereby adjusting the angle of the light dispersed by the diffraction grating 13 in the direction indicated by arrow R2. For ease of explanation, FIG. 1 shows white light L0 split into three light components: blue light Lb, green light Lg, and red light Lr. However, as described above, white light L0 contains an equal mixture of all wavelengths of light contained in visible light, and in reality, it is split into multiple colors (purple, light blue, yellow, orange, etc.).

[0016] By operating the electric motor that constitutes the angle adjustment means 12, the angle of the light dispersed by the diffraction grating 13 is changed, and as shown in the figure, pinhole H of pinhole mask 14 selects light of a specific wavelength (for example, blue light Lb) from the light of multiple wavelengths dispersed by the diffraction grating 13. Then, by changing the angle of the diffraction grating 13 at high speed by the angle adjustment means 12, the light reflected by the optical path conversion mirror 15 and irradiated from the light irradiation unit 10 changes with a time lag into blue light Lb, green light Lg, and red light Lr.

[0017] The above Reference example According to the light irradiation device 1A configured as above, an inexpensive light irradiation device is provided that can disperse white light into a plurality of wavelengths at different times and irradiate the light with a simple configuration.

[0018] Figure 2 Based on this, the first light irradiation device one A light irradiation device 1B configured as this embodiment will be described.

[0019] The light irradiation device 1B is equipped with a white light source 11, a diffraction grating 13, and a pinhole mask 14 that selects light of multiple wavelengths (blue light Lb, green light Lg, red light Lr, etc.) using a pinhole H, similar to those of the light irradiation device 1A described based on FIG. 1. In addition to these, the light irradiation device 1B is equipped with a first condenser mirror 16 that reflects light of multiple wavelengths dispersed by the diffraction grating 13, a second condenser mirror 17 that has the same focal length as the first condenser mirror 16 and is arranged in a position symmetrical with respect to the focus indicated by point C in the figure, an optical path conversion mirror 15 that converts the optical path positioned at the focus of the second condenser mirror 17, and an angle adjustment means 12 that changes the reflection angle of the optical path conversion mirror 15. Note that the angle of the diffraction grating 13 of this light irradiation device 1B is fixed, unlike the light irradiation device 1A described above. one According to the light irradiation device 1B shown as this embodiment, the light of a plurality of wavelengths (blue light Lb, green light Lg, red light Lr) diffracted and dispersed by the diffraction grating 13 is collected by the concave collecting surface 16a of the first collecting mirror 16 and directed to the second collecting mirror 17, and further, the light collected by the concave collecting surface 17a of the second collecting mirror is directed to the pinhole mask 14. one The light selecting means in this embodiment is configured to include a first collecting mirror 16, a second collecting mirror 17, an optical path conversion mirror 15, an angle adjusting means 12, and a pinhole mask 14. The optical path conversion mirror 12 is preferably selected from a galvano scanner, a resonant scanner, or a polygon mirror, which are capable of changing the reflection angle at high speed.

[0020] As the light irradiation device of the present invention, the light irradiation device 1B shown in FIG. 2 is used, and the white light source 11 is operated, and the angle adjusting means 12 is operated based on an instruction signal from the control means 100 to change the angle of the optical path conversion mirror 15 in the direction shown by the arrow R3, whereby the angle of the light reflected by the optical path conversion mirror 15 is adjusted in the direction shown by the arrow R4, and the above Reference example Similarly, by changing the wavelength of the light selected by the pinhole H of the pinhole mask 14, the light irradiated from the light irradiating unit 10 can be changed to blue light Lb, green light Lg, and red light Lr with a time difference. Reference example Similarly, an inexpensive light irradiation device can be provided that uses a simple configuration to split white light into wavelengths at different times and irradiate the light.

[0021] figure 3, the first light irradiation device of the present invention two A light irradiation device 1C configured as this embodiment will be described.

[0022] 3, in addition to the components arranged in light irradiation device 1B described based on Fig. 2, light irradiation device 1C includes a third collecting mirror 18 between optical path conversion mirror 15 and pinhole mask 14, and is set so that the focus of light collected by concave collecting surface 18a of third collecting mirror 18 is positioned at pinhole mask 14. Furthermore, light irradiation device 1C includes a reflecting mirror 19 that reflects light that has passed through pinhole H in pinhole mask 14. Note that reflecting mirror 19 adjusts the optical path in any direction and is not an essential component in the present invention; light that has passed through pinhole H in pinhole mask 14 may be irradiated directly from light irradiation unit 10.

[0023] This two In the light irradiation device 1C shown as this embodiment, the angle of the optical path conversion mirror 15 is changed in the direction shown by the arrow R5 based on the instruction signal from the control means 100, and the angle of the light reflected by the optical path conversion mirror 15 is changed in the direction shown by the arrow R6. two The light selection means in this embodiment includes the first collecting mirror 16, the second collecting mirror 17, the optical path conversion mirror 15, the angle adjustment means 12, and the pinhole mask 14, as well as a third collecting mirror 18.

[0024] In the light irradiation device 1C, the third condenser mirror 18 is used to condense the light from the pinhole mask 1 The blue light Lb, green light Lg, red light Lr, etc. are condensed by the pinhole H arranged in 4, Reference example, firstCompared with the light irradiation device 1A and the light irradiation device 1B constituting the embodiment, it is possible to more specifically select the wavelength of light passing through the pinhole H of the pinhole mask 14, and an inexpensive light irradiation device is provided which disperses and irradiates white light with a clearer time difference corresponding to a plurality of wavelengths.

[0025] In addition, the above-mentioned two The light conversion mirror 15 constituting the light selection means in the light irradiation device 1C of the embodiment is also preferably selected from a galvanometer scanner, a resonant scanner, or a polygon mirror that can change the reflection angle at high speed. By selecting such a configuration, it becomes possible to irradiate light of multiple specific wavelengths successively from the light irradiation unit 10 with a smaller time difference, and when this light irradiation device is applied to a technology for measuring wafer thickness, it becomes possible to measure the wafer thickness more efficiently. [Explanation of symbols]

[0026] 1A, 1B, 1C: Light irradiation device 10: Light irradiation unit 11: White light source 12: Angle adjustment means 13: Diffraction grating 14: Pinhole mask 15: Optical path conversion mirror 16: First focusing mirror 16a: Focusing surface 17: Second focusing mirror 17a: Focusing surface 18: Third focusing mirror 18a: Focusing surface 19: Reflective mirror 100: Control means H: Pinhole L0: white light Lb: Blue light Lg:green light Lr: Red light

Claims

1. A light irradiation device that splits white light into a plurality of wavelengths and irradiates the light, The optical system includes a white light source, a diffraction grating that separates the white light emitted by the white light source, and a light selecting means that selects light of a specific wavelength from the light of multiple wavelengths separated by the diffraction grating, The light selecting means is a means for selecting light of a specific wavelength from light of multiple wavelengths dispersed by the diffraction grating by passing it through, and the light irradiation device includes: a first focusing mirror that reflects light of multiple wavelengths dispersed by the diffraction grating; a second focusing mirror that has the same focal length as the first focusing mirror and is arranged in a position that is point-symmetrical with the focus as the center of symmetry; an optical path conversion mirror that is positioned at the focus of the second focusing mirror and changes the optical path; and a means for selecting and passing light of multiple wavelengths whose optical path has been converted by the optical path conversion mirror.

2. 2. The light irradiation device according to claim 1, further comprising a third focusing mirror disposed downstream of the optical path conversion mirror, the focal point of the third focusing mirror being positioned at a means for selectively transmitting light of the plurality of wavelengths whose optical paths have been converted by the optical path conversion mirror.

3. 3. The light irradiation device according to claim 1, wherein the means for selectively passing the light of a plurality of wavelengths whose optical paths have been changed by the optical path changing mirror is a pinhole mask.

4. A light irradiation device described in any one of claims 1 to 3, wherein the optical path conversion mirror includes either a galvano scanner, a resonant scanner, or a polygon mirror.

5. A light irradiation device described in any one of claims 1 to 4, wherein the white light source is one of an SLD light source, an ASE light source, an LED light source, a supercontinuum light source, a halogen light source, a xenon light source, a mercury light source, and a metal halide light source.

Images