TW201812422A - Wavelength conversion device that is capable of efficient conversion of wavelength in using a wavelength conversion means to convert wavelength of pulse laser beam having a wide spectrum width - Google Patents

Abstract

An objective of the present invention is an invention based on the above facts and a primary technical objective is to provide a wavelength conversion device, which is capable of efficient conversion of wavelength in using a wavelength conversion means to convert wavelength of pulse laser beam having a wide spectrum width. According to the present invention, a wavelength conversion device that converts the wavelength of a pulse laser beam is provided and is made up at least the following: an oscillator that oscillates a pulse laser beam; a wavelength selection means that selects at least two wavelengths of pulse laser beams among spectrum widths of the pulse laser beam oscillated by the oscillator; a delay time generating means that generates a time interval between the at least two selected kinds of pulse laser beams by applying a delay time to at least one pulse laser beam among the pulse laser beams of the selected wavelengths; an energy amplifying means that amplifies energy of each of the pulse laser beams that generates the time interval; a delay time correcting means that makes the amplified pulse laser beams of at least two kinds of wavelengths progress at the same time by correcting the delay time; and a wavelength conversion means that converts the wavelengths of the pulse laser beams of at least two wavelengths and progressing at the same time.

Description

   Wavelength conversion device   

The present invention relates to a wavelength conversion device that converts the wavelength of pulsed laser light.

A wafer formed on the surface by dividing a plurality of devices such as ICs and LSIs by dividing a predetermined line. A laser processing device is used to irradiate laser light onto the predetermined dividing line and divide it into devices one by one. Appliances such as mobile phones and personal computers.

The laser processing device includes at least a holding means for holding the workpiece and a laser light irradiating means for irradiating laser light to the processed object held by the holding means; the laser ray irradiating means is composed of the following : Oscillates a laser beam oscillator that applies laser beams of the processing wavelength to the workpiece; focuses the laser beam oscillated by the laser beam oscillator and irradiates the laser beam to be held by the holding means An optical system such as an attenuator that adjusts the output of laser light and a beam expander that adjusts the beam diameter, which are arranged between the laser light oscillator and the condenser; The object to be processed is subjected to desired processing (for example, see Patent Document 1).

Moreover, when the wavelength of the laser light oscillated by the laser ray oscillator is short wavelengths such as 355 nm and 266 nm, the optical system is damaged in a relatively short time and the optical system must be exchanged at a high frequency. There are uneconomic issues. In order to solve such a problem, the wavelength of the laser light oscillated by the laser ray oscillator is set to a relatively long wavelength such as 1064 nm. In front of the condenser, a non-linear optical crystal (for example, LBO: LiB ₃ O ₅ lithium triborate, etc.) is being developed to convert short-wavelength laser light such as 355 nm (see, for example, Patent Document 2).

    [Previous Technical Literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2006-108478

[Patent Document 2] Japanese Patent Laid-Open No. 2013-193090

However, when an optical fiber laser is used as the oscillation source of the laser light, the peak power of the laser light is high, and the phase modulation is caused by the phase shift due to the Self Phase Modulation (SPM) effect. Unfortunately, there is a widening of the spectral bandwidth. When the spectral bandwidth is so wide, when the wavelength is converted by a wavelength conversion means such as a non-linear optical crystal, for example, conversion of laser light from a wavelength of 1064 nm to a wavelength of 355 nm causes a problem that conversion efficiency deteriorates.

The present invention was created in view of the above-mentioned facts, and its main technical problem is to provide a wavelength conversion device that can efficiently perform pulse wavelength conversion of pulsed laser light with a wide spectral bandwidth by means of wavelength conversion. Perform wavelength conversion.

In order to solve the above-mentioned main technical problems, according to the present invention, a wavelength conversion device for converting the wavelength of pulsed laser light is provided, which is constituted by at least the following: an oscillator that oscillates pulsed laser light, and an oscillator that oscillates from the oscillator. Among the spectral bandwidth of the pulsed laser light, a wavelength selection means for selecting at least two types of pulsed laser light, and a delay time of at least any one of the pulsed laser light from the selected selected pulsed laser light is provided. The selected delay time generation means of at least two types of pulsed laser light generation time intervals, the energy amplification means that amplifies the energy of each of the pulsed laser light generated at the time interval, and allows the delay time to be corrected The travel of the amplified pulse laser light of at least two types of wavelengths is the same delay time correction means, and the wavelength conversion means of converting the wavelengths of the pulse laser light of at least two types of wavelengths that travel simultaneously.

It can be constituted that: the oscillator oscillates pulsed laser light having a spectral bandwidth with a wavelength of 1064 nm as the apex; the wavelength selection means selects two types of pulsed laser light with a wavelength near 1064 nm; Generates pulsed laser light with a wavelength of 532nm.

It may be configured that the wavelength conversion device further includes a wavelength separation means and a wavelength synthesis means; the delay time correction means includes: a first delay time correction means and a second delay time correction means; and the wavelength conversion means includes : The first wavelength conversion means and the second wavelength conversion means; the oscillator oscillates a pulsed laser light having a spectral bandwidth with a wavelength of 1064 nm as the apex; the wavelength selection means selects and outputs three types in the vicinity of 1064 nm Pulse laser light of a wavelength of 5 to 5; the delay time generating means is to give a delay time to at least two types of pulse laser light of the three types of pulse laser light, Generate a time interval, and use the energy amplifying means to amplify the energy of the three types of pulsed laser light; amplify the pulsed laser light of the three types of wavelengths of each energy by using the wavelength separation means to separate into two pulses A laser ray and a pulsed laser ray; the two pulsed laser ray are guided to constitute the delay time correction The first delay time correction means of the segment and the first wavelength conversion means constituting the wavelength conversion means are converted into pulse laser light with a wavelength of 532 nm and reach the wavelength synthesis means; the one pulse laser light is guided to The second delay time correcting means and the wavelength synthesizing means constituting the delay time correcting means make the travel the same through the action of the delay time correcting means, and the pulsed laser light rays synthesized by the wavelength synthesizing means are constituted by The second wavelength conversion means of this wavelength conversion means converts the pulsed laser light having a wavelength of 355 nm.

The wavelength conversion device of the present invention is configured using at least an oscillator that oscillates pulse laser light, and a pulse laser having at least two types of wavelengths selected from the spectral bandwidth of the pulse laser light oscillated by the oscillator. A means for selecting the wavelength of the emitted light, and providing a delay time for at least one of the pulsed laser light rays from the selected pulsed laser light rays, and a delay time for generating a time interval between the selected at least two types of pulsed laser light rays. The generating means, an energy amplifying means that amplifies the energy of each of the pulsed laser rays that generates the time interval, and makes the travel of the pulsed laser rays of at least two types of wavelengths that have been amplified by correcting the delay time the same Delay time correction means, a wavelength conversion means that converts the wavelengths of at least two types of pulsed laser light traveling at the same time; after this, even the laser light with a wide spectral bandwidth is oscillated from the laser light oscillator It is also possible to narrow the spectral bandwidth of the pulsed laser light that is guided to the wavelength conversion means, and to make the wavelength change The conversion efficiency means to enhance the effect.

10‧‧‧ wafer

40‧‧‧laser processing device

41‧‧‧ abutment

42‧‧‧ means of retention

43‧‧‧ Means of movement

44‧‧‧Laser light irradiation mechanism

44a‧‧‧Condenser

44b‧‧‧Oscillator

44c, 44c ' ‧‧‧ Wavelength Converter

441, 461‧‧‧ wavelength selection means

442, 462‧‧‧‧ Delay generation method

443, 463‧‧‧ Energy Amplification Means

444‧‧‧ Delay time correction method

445‧‧‧wavelength conversion means

464‧‧‧wavelength separation means

465‧‧‧The first delay time correction method

466‧‧‧The first wavelength conversion method

467‧‧‧The second delay time correction method

468‧‧‧Wavelength synthesis method

469‧‧‧Second wavelength conversion method

FIG. 1 is an overall perspective view of a laser processing apparatus including a wavelength conversion device constructed according to the present invention.

FIG. 2 is a block diagram for explaining an outline of an embodiment of the wavelength conversion device of the present invention.

3 is a block diagram for explaining the outline of another embodiment of the wavelength conversion device of the present invention.

Hereinafter, embodiments of the wavelength conversion device according to the present invention will be described in further detail with reference to the drawings.

FIG. 1 is an overall perspective view illustrating a laser processing device 40 as a processing device including the wavelength conversion device of the present invention. The laser processing apparatus 40 shown in the figure includes a base 41, a holding means 42 for holding the wafer 10, which is held to the ring-shaped frame F by, for example, an adhesive tape T, and a moving means for moving the holding means 42 43, and a laser light irradiating mechanism 44 for irradiating laser light on the workpiece held by the holding means 42.

The holding means 42 includes a rectangular X-shaped movable plate 60 mounted on the base 41 and freely moving in the X direction indicated by an arrow X in the figure, and a freely moving Y direction indicated by an arrow Y in the figure. A rectangular Y-shaped movable plate 61 mounted on the X-directional movable plate 60, a barrel-shaped pillar 62 fixed to the upper surface of the Y-directional movable plate 61, and a rectangular-shaped cover plate 63 fixed to the upper end of the pillar 62 are mounted. On the upper surface of the holding table 64 of the circular workpiece held by the cover plate 63 extending upward through the long hole formed in the cover plate 63, a porous material is disposed and extends substantially horizontally. The circular shaped suction chuck 65. The suction chuck 65 is connected to a suction means (not shown) through a flow path passing through the stay 62. Furthermore, the X direction is the direction indicated by the arrow X in FIG. 1, and the Y direction is the direction indicated by the arrow Y in FIG. 2, that is, the direction orthogonal to the X direction. The planes defined in the X and Y directions are substantially horizontal.

The moving means 43 includes an X-direction moving means 80 and a Y-direction moving means 82. The X-direction moving means 80 and the X-direction moving means 80 convert the rotary motion of the motor into a linear motion and transmit it to the X-direction movable plate 60. The X-direction movable plate 60 advances and retreats along the guide rails on the base 41. X direction. The Y-direction moving means 82 converts the rotational movement of the motor into linear motion and transmits it to the Y-direction movable plate 61. The Y-direction movable plate 61 advances and retreats in the Y direction along the guide rails on the X-direction movable plate 60. Although the illustration is omitted, position detection means are respectively provided in the X-direction moving means 80 and the Y-direction moving means 82 to accurately detect the position in the X direction, the position in the Y direction, and the rotation in the circumferential direction of the holding table 64. For the position, the X-direction moving means 80 and the Y-direction moving means 82 are driven according to the signals indicated by the control means described later, so that the bed 64 can be accurately positioned at an arbitrary position and angle.

As shown in FIG. 2, the laser light irradiating mechanism 44 includes at least a condenser 44 a that condenses the pulsed laser light and irradiates the workpiece, and an oscillator 44 b that oscillates the pulsed laser light and converts the laser light from the laser 44. A wavelength conversion device 50 constituted by a wavelength conversion section 44c of the wavelength of the pulsed laser light oscillated by the oscillator 44b. In addition, although omitted in the figure, the laser light irradiation mechanism 44 may further include a mirror for deflecting the optical path, an attenuator for adjusting the output, and a crystal to be applied to the adsorption chuck 65. Various devices such as imaging means for processing marks on the circle 10 are not impeded by the provision of structures other than the illustration.

The oscillator 44b for oscillating pulsed laser light is a fiber laser oscillator that oscillates a pulsed laser light having a wavelength of 1064 nm as a vertex. The pulsed laser light λ irradiated from this oscillator 44b is as shown in FIG. 2, the horizontal axis is the wavelength (w), and the vertical axis is the spectral density. In the case of its distribution, the effect of the self-phase modulation effect is shown. , With a spectral bandwidth containing wavelengths from 1062nm to 1066nm.

The wavelength conversion unit 44c is provided with at least: a wavelength selection means 441, a delay time generation means 442, an energy amplification means 443, a delay time correction means 444, and a wavelength conversion means 445 for selecting two wavelengths; This is explained below.

The pulse laser light λ having a spectral bandwidth of the above-mentioned 1062 nm to 1066 nm wavelength oscillated by the oscillator 44b is made incident on the wavelength selection means 441. The wavelength selection means 441 is configured by selectively separating the incident pulse laser light λ into a pulse laser light λ1 having a wavelength of 1062 nm and a pulse laser light λ 2 having a wavelength of 1066 nm to emit each optical filter. Device.

Next, the pulsed laser light rays λ1 and λ2 output from the wavelength selection means 441 are incident on the delay time generation means 442. The delay time generating means 442 is formed by, for example, a volume Bragg grating (VBG), a fiber Bragg grating (FBG), or other general diffraction gratings, and is set to extend at least one of The optical path length makes the passing time of the pulsed laser light λ2 longer, and a specified delay time occurs with respect to the pulsed laser light λ1. Next, the delay time is generated, and thereafter, between the pulsed laser light λ1 and the pulsed laser light λ2, a time interval based on a specified delay time is generated, and the pulsed laser light is emitted from the delay time generating means 442. λ1, pulsed laser light λ2.

Next, the pulsed laser light rays λ1 and λ2 emitted from the delay time generating means 442 are incident on the energy amplifying means 443, and each output (pulse energy) is amplified and emitted.

The pulsed laser light rays λ1 and λ2 amplified by the energy amplifying means 443 are incident on the delay time correcting means 444. The pulsed laser rays λ1 and λ2 incident on the delay time correction means 444 pass through the function of the above-mentioned delay time generating means 442. The pulsed laser rays λ2 travels with a specified delay time with respect to the pulsed laser rays λ1. Only the specified delay time portion generates a time interval. Here, the delay time correcting means 444 has a configuration that delays the pulse laser beam λ1 that advances only by the specified time, and eliminates the two pulse laser beams λ1 and λ2 that have been incident with a time interval. At time intervals, the pulse laser rays λ1 and λ2 that are output as two wavelengths evolve into the same pulse laser rays λ3. In addition, the structure for generating the delay time for the pulsed laser light λ1 and dissolving the time interval is slightly the same as the structure for generating the delay time for the pulsed laser light λ2 in the above-mentioned delay time generating means 442 (only delayed The pulse laser light has a different wavelength), and its detailed description is omitted.

The pulsed laser light λ3 emitted from the delay time correction means 444 is incident on the wavelength conversion means 445. As the wavelength conversion means 445 may be employed conventional general nonlinear optical crystal (e.g., LBO: LiB ₃ O ₅ three lithium borate). Next, the pulsed laser light λ3 incident on the wavelength conversion means 445 is converted into a pulsed laser light with a wavelength of 532 nm and emitted. As described above, the pulsed laser light λ oscillated from the oscillator 44 b is subjected to wavelength conversion by the wavelength conversion unit 44 c.

According to the above-mentioned wavelength conversion device 50 constituted by the present invention, for example, even when pulse laser light whose spectral bandwidth is widened is subjected to wavelength conversion in a fiber laser oscillator, pulses of two types of wavelengths are selectively taken out. Laser light is used as seed light with narrow spectral lines. Next, the output of each pulsed laser beam is amplified by causing a delay time to occur for at least one of them, and after performing the amplification, the time interval generated through the delay time is eliminated, and two types are allowed. The progress of the pulsed laser light is the same, and wavelength conversion is performed by means of wavelength conversion. As a result, high wavelength conversion efficiency can be achieved, and processing efficiency can be improved when laser processing is performed.

Furthermore, in the above-mentioned wavelength selection means 441, a pulsed laser light with a wavelength of 1062 nm and a pulsed laser light with a wavelength of 1066 nm are selectively extracted from the pulsed laser light oscillated by the oscillator 44b; A combination of two types of wavelengths is selected. For example, a pulsed laser light with a wavelength of 1063 nm and a pulsed laser light with a wavelength of 1065 nm may be selected as long as the spectrum of the pulsed laser light λ oscillated by the oscillator 44b is selected. For two types of pulse lasers with different wavelengths, any combination of wavelengths is possible.

Referring to FIG. 3, another embodiment of the wavelength conversion device according to the present invention will be described. The laser beam irradiating mechanism 44 also shown in FIG. 3 is similar to the embodiment described in FIG. 2 described above. The laser beam irradiating unit 44 b oscillates a pulsed laser beam having a spectral bandwidth of 1064 nm to 1066 nm with a vertex of 1064 nm and a wavelength conversion unit 44c ' and the condenser 44a constitute the same point. Further, in comparison with the embodiment of FIG. 2 described above, in the two wavelength conversion units 44c ′ , the incident pulse laser light λ is converted into a pulse laser light with a wavelength of 355 nm and emitted. This point of difference will be described mainly.

The wavelength conversion unit 44c ' includes: wavelength selection means 461 for selecting three wavelengths, delay time generation means 462, energy amplification means 463, wavelength separation means 464, first delay time correction means 465, first wavelength conversion means 466, The second delay time correcting means 467, the wavelength synthesizing means 468, and the second wavelength converting means. The function of the wavelength converting section 44c ' will be described below.

The pulsed laser light λ having a spectral bandwidth of 1062 nm to 1066 nm oscillated by the oscillator 44b is first incident on the wavelength selection means 461. The wavelength selection means 461 selectively separates the incident pulse laser light λ into a pulse laser light λ1 having a wavelength of 1062nm, and a pulse laser light λ2 having a wavelength of 1066nm, and a pulse laser light having a wavelength of 1064nm. λ4, and each shot.

The pulsed laser light rays λ1, λ2, and λ4 selected by the wavelength selection means 461 are incident on the delay time generation means 462, and at least two types of pulsed laser light rays (in this embodiment, the pulsed laser light rays λ1, λ2) The delay time is given only for a specified time, and emitted in the same time interval in the order of the pulsed laser rays λ4, λ1, and λ2. Next, the pulsed laser beams λ4, λ1, and λ2 given the time interval are incident on the energy amplifying means 463.

The pulsed laser light rays λ4, λ1, and λ2 incident on the energy amplifying means 463 are respectively amplified by energy and emitted, and are incident on the wavelength separating means 464. The wavelength separation means 464 may have the same structure as the wavelength selection means 461, and may include an optical filter that transmits the wavelengths of the pulsed laser light rays λ1 and λ2, and an optical filter that branches the wavelengths of the pulsed laser light rays λ4. After this, the pulsed laser light rays λ1, λ2, and the pulsed laser light rays λ4 are allowed to be emitted to different optical paths, respectively.

The pulsed laser light rays λ1 and λ2 separated by the wavelength separation means 464 are sent to the first delay time correction means 465 at the time interval given by the delay time generation means 462, and are passed through the first delay time correction means 465. The effect is to give a delay time to the preceding pulsed laser ray λ1 only for a specified time, after which the time interval is eliminated and synthesized to make it travel the same as the pulsed laser ray λ2.

The first delay time correcting means 465 dissolves the delay time and synthesizes the pulsed laser light rays λ1 and λ2 that travel simultaneously. The pulsed laser light rays λ1 and λ2 travel at the same time. In addition, the first delay time correction means 465 and the first wavelength conversion means 466 of this embodiment may have the same configurations as the delay time correction means 444 and the wavelength conversion means 445 of the embodiment shown in FIG. 2 described above.

The other pulsed laser light λ4 separated by the wavelength separation means 464 is incident on the second delay time correction means 467. In the second delay time correction means 467, the incident pulse laser light λ4 passes through other light paths so as to travel in the same way as the pulse laser light λ3 synthesized in a later process, that is, only the previous delay is corrected. The delay time given to the pulsed laser light λ2 in the time generating means 462 is adjusted so as not to generate a time interval for the pulsed laser light λ3 at the time of post-process synthesis.

The pulsed laser light λ3 converted into a pulsed laser light with a wavelength of 532nm and the pulsed laser light λ4 with a wavelength of 1064nm adjusted with a delay time are irradiated into a wavelength synthesizing means 468 and synthesized. The wavelength synthesizing means 468 may be an optical means that transmits only a specific wavelength and reflects light of other wavelengths. Using such a wavelength synthesizing means 468, the pulsed laser light λ4 having a wavelength of 1064 nm is transmitted, and the pulsed laser light λ3 having a wavelength of 532 nm converted in the wavelength conversion means 467 is reflected so that the optical paths are uniform, and the pulsed laser light λ3 is synthesized. And λ4.

The pulsed laser light rays λ3 and λ4 synthesized by the wavelength synthesizing means 468 are incident on the second wavelength conversion means 469, and the pulsed laser light rays λ5 having a wavelength of 355 nm are emitted. The second wavelength conversion means 469 is composed of a non-linear crystal that can obtain laser light with a wavelength of 355 nm by emitting pulsed laser light with two types of wavelengths (532 nm, 1064 nm). For example, LBO: LiB ₃ can be used. O ₅ lithium triborate). In addition, the LBO is a non-linear crystal of the same raw material as the first wavelength conversion means; however, the LBO of the first wavelength conversion means has a different crystal axis orientation and is produced in accordance with the wavelength to be converted.

The wavelength conversion unit 44c ′ in this embodiment is configured as described above, and the pulse laser light λ having a wide spectral bandwidth oscillated by the oscillator 44b is efficiently converted into a pulse laser light λ5 having a wavelength of 355 nm. The processed object, that is, the wafer 10 is radiated through the condenser 44a.

Claims (3)

    A wavelength conversion device for converting the wavelength of a pulsed laser light, which is composed of at least: an oscillator that oscillates a pulsed laser light, and at least two types selected from the spectral bandwidth of the pulsed laser light oscillated by the oscillator. The wavelength selection means of the pulsed laser light of a wavelength of at least one is given a delay time to at least any one of the pulsed laser light from the selected pulsed laser light of a wavelength, and is generated from the selected at least two types of pulsed laser light. Means for generating a delay time of a time interval, means for amplifying the energy of each of the pulsed laser rays that generate the time interval, and at least two types of pulsed laser light of a wavelength that have been amplified by correcting the delay time Is a wavelength conversion means that converts the wavelengths of pulsed laser light of at least two types of wavelengths that are traveling at the same time.         For example, the wavelength conversion device according to claim 1, wherein the oscillator oscillates a pulsed laser light having a spectral bandwidth with a wavelength of 1064 nm as the apex; the wavelength selection means selects two types of wavelengths around 1064 nm. Pulsed laser light; this wavelength conversion means generates pulsed laser light with a wavelength of 532 nm.         For example, the wavelength conversion device of claim 1 further includes a wavelength separation means and a wavelength synthesis means; the delay time correction means includes: a first delay time correction means and a second delay time correction means; the wavelength conversion The means includes: a first wavelength conversion means and a second wavelength conversion means; the oscillator oscillates a pulsed laser light having a spectral bandwidth with a wavelength of 1064 nm as the apex; the wavelength selection means selects and outputs around 1064 nm Pulse laser light of three types of wavelengths; The delay time generating means is to give a delay time to pulse laser light of at least two types of wavelengths of the pulse laser light of three types of wavelengths in the three types of pulses. The laser light generates a time interval, and the energy of the three types of pulsed laser light is amplified by the energy amplifying means; the pulsed laser light of the three types of wavelengths that amplifies each energy is separated into the wavelength separation means into 2 pulsed laser rays and 1 pulsed laser beam; the 2 pulsed laser rays are guided to constitute the delay time The first delay time correction means of the positive means and the first wavelength conversion means constituting the wavelength conversion means are converted into pulse laser light having a wavelength of 532 nm and reach the wavelength synthesis means; the one pulse laser light is guided. The second delay time correcting means and the wavelength synthesizing means constituting the delay time correcting means make the travel the same through the effect of the delay time correcting means, and the pulsed laser light synthesized by the wavelength synthesizing means is The second wavelength conversion means constituting the wavelength conversion means converts the pulsed laser light having a wavelength of 355 nm.