JP5884087B2 - Laser processing method and laser processing apparatus - Google Patents

Description

  The present invention relates to a laser processing method and a laser processing apparatus that perform processing by irradiating a substrate with laser light.

  For example, when a wafer composed of a large number of infrared sensor chips is a substrate, the substrate is generally made of a ferroelectric material such as lithium tantalate, and nickel thin films are formed on both surfaces of the substrate. Generally, it is formed. And in such a board | substrate, it may be necessary to perform the process which forms a through-groove in the vicinity area | region of a nickel thin film, and it is proposed to perform the process by a laser process.

JP 2010-212478 A

  By the way, the nickel thin film of the wafer is an anaerobic portion that dislikes thermal effects. Therefore, when the processing is performed by laser processing, it is required to minimize the thermal influence on the nickel thin film. Moreover, in order to improve productivity, it is also required to process at as high a speed as possible.

  An object of the present invention is to provide a laser processing method and a laser processing apparatus capable of minimizing the thermal influence on an anaerobic portion of a substrate as much as possible and processing the substrate at a high speed.

A first aspect of the present invention is a laser processing method for forming a through-groove by irradiating a laser beam to a region near the anaerobic portion with respect to a substrate having an anaerobic portion that dislikes thermal influence, among the neighboring region, the near region portion unpleasant heat portion is irradiated with a laser beam to form a through groove in the ablation processing conditions, and ablation processing step, among the neighboring region, far region portion from the unpleasant heat portion , in the thermal processing conditions by irradiating a laser beam to form a through-groove, and a heat processing step, and have a, after performing the heat processing step, for performing said ablation processing step, as characterized by Yes.

  The “region portion close to the anaerobic portion” is a portion that has a thermal effect on the anaerobic portion if thermal processing is performed.

This laser processing method preferably further employs the following specific configuration as appropriate.
( D) The ablation process is performed using an ultrashort pulse laser oscillator that outputs laser light having a pulse width of 100 femtoseconds to 100 picoseconds.

According to a second aspect of the present invention, there is provided a laser processing apparatus for forming a through groove by irradiating a region near the anaerobic portion with a laser beam on a substrate having an anaerobic portion that is averse to thermal influence, a first laser oscillator for outputting a laser beam to form a through groove in processing conditions, and the second laser oscillator for outputting a laser beam to form a through groove in thermal processing conditions, the output from the first laser oscillator The irradiation position of the laser beam to be applied is set in an area portion close to the anaerobic portion in the vicinity area, and the irradiation position of the laser light output from the second laser oscillator is set in the vicinity area. among them, the region far part from the bad heat portion, sets a position control unit, the first laser oscillator and the second laser oscillator, the first laser oscillator after the second laser oscillator is operated actuation In so that controls, it is characterized by comprising a timing controller, a.

This laser processing apparatus preferably further employs the following specific configuration as appropriate.
(E) The first laser oscillator is an ultrashort pulse laser oscillator that outputs laser light having a pulse width of 100 femtoseconds to 100 picoseconds.

According to the laser processing method of the first aspect of the present invention, the laser beam is irradiated under the thermal processing conditions on the vicinity region of the anaerobic portion, so that the processing can be performed with good workability, and the region within the vicinity region Since the laser beam is irradiated to the region portion close to the thermophilic portion under the ablation processing conditions, it is possible to suppress the thermal effect on the thermophilic portion. Therefore, according to the laser processing method of the present invention, the thermal influence on the anaerobic portion of the substrate can be minimized and the substrate can be processed at high speed.
Moreover, since the thermal processing step is performed first, the ablation processing is performed in a state in which the through groove is formed by the thermal processing. Therefore, the surface area for evaporating or scattering the substrate material in the ablation processing is larger than that in the case of performing the ablation processing first. Therefore, according to the laser processing method of the present invention, the workability of the ablation process can be improved, and the substrate can be processed at a higher speed.

  According to the laser processing apparatus of the second aspect of the present invention, the laser processing method of the present invention can be reliably implemented.

1 is a schematic side view showing a laser processing apparatus of the present invention. It is a plane fragmentary figure which shows the state after the process of the board | substrate planned. It is a plane fragmentary figure which shows the state after the process which the chip | tip in a board | substrate is planned. It is sectional drawing of the board | substrate processed by the laser processing method of this invention. It is sectional drawing which shows one work process of the laser processing method which concerns on 1st Embodiment. FIG. 6 is a cross-sectional view showing one work process following FIG. 5. It is sectional drawing which shows the process part after the process of FIG. It is sectional drawing which shows one work process of the laser processing method which concerns on 2nd Embodiment. FIG. 9 is a cross-sectional view showing one work process following FIG. 8. It is sectional drawing which shows one work process of the laser processing method which concerns on 3rd Embodiment.

Hereinafter, although an embodiment of the present invention is described, a 2nd embodiment is an embodiment of the present invention, and the 1st and 3rd embodiments are reference forms.
[First Embodiment]
FIG. 1 is a schematic side view showing a laser processing apparatus according to the present embodiment. The laser processing apparatus 5 includes a first laser oscillator 51A, a second laser oscillator 51B, a processing stage 52, and an operation control unit 53.

  The first laser oscillator 51A is set so as to output laser light 9A under the ablation processing condition vertically downward through the lens 519A. Specifically, the first laser oscillator 51A is an ultrashort pulse laser oscillator that outputs laser light having a pulse width of 100 femtoseconds to 100 picoseconds. The second laser oscillator 51B is set so as to output the laser light 9B under the thermal processing condition, vertically downward through the lens 519B.

  The processing stage 52 is configured to hold the substrate 1 to be processed on the stage main body 521. The processing stage 52 includes a drive mechanism 522. The drive mechanism 522 can move the stage main body 521 in the vertical direction and the horizontal direction. That is, the drive mechanism 522 can arbitrarily set the processing position of the substrate 1 with respect to each of the irradiated laser beams 9A and 9B by moving the stage main body 521. The processing stage 52 preferably further includes a reversing mechanism 523. The reversing mechanism 523 is configured so that the substrate 1 on the stage main body 521 can be gripped, lifted upside down, and placed on the stage main body 521.

  The operation control unit 53 includes a position control unit and a timing control unit. The position control unit controls the drive mechanism 522 to set the first processing position of the substrate 1 processed by the laser light 9A and the second processing position of the substrate 1 processed by the laser light 9B. Yes. The timing control unit controls the operation timing of the first laser oscillator 51A and the second laser oscillator 51B.

  The substrate 1 is a lithium tantalate wafer and includes a large number of infrared sensor chips. Lithium tantalate is a brittle material. As shown in FIG. 2 which is a partial plan view, the substrate 1 is scheduled to be cut for each infrared sensor chip 10 by the through groove 2A. Further, in the infrared sensor chip 10, as shown in FIG. 3 which is a plan view, an infrared light receiving unit 100 is provided on the surface of the substrate 1, and along the three sides of the infrared light receiving unit 100 for heat insulation. The through groove 2B is scheduled to be formed. The infrared light receiving unit 100 is made of a nickel thin film and is a thermophilic part that dislikes the influence of heat, and is formed on both surfaces of the substrate 1. That is, as shown in FIG. 4, in the substrate 1, a nickel thin film 31 is formed on one surface 11 and a nickel thin film 32 is formed on the other surface 12. The through groove 2 formed in the substrate 1 by the laser processing apparatus 5 of the present embodiment is one or both of the through groove 2A and the through groove 2B. Here, a case where the through groove 2B is formed will be described. In FIG. 4, a region where the through groove 2 </ b> B is to be formed is illustrated as a vicinity region 200 of the infrared light receiving unit 100.

  Formation of the through groove 2B by the laser processing method using the laser processing apparatus 5 of the present embodiment is performed as follows.

(1) First, the drive mechanism 522 is controlled by the position controller, and moves the stage body 521 to set the substrate 1 to the first processing position. As shown in FIG. 5, the first processing position is a position where the laser light 9 </ b> A irradiates a region portion 201 close to the infrared light receiving unit 100 in the vicinity region 200.

(2) Next, the first laser oscillator 51A is operated by the control by the timing control unit, and continues the irradiation of the laser light 9A in the state of FIG. 5 (ablation processing step). Since the laser beam 9A is irradiated under the ablation processing conditions, the region portion 201 is ablated, and a through groove 21B is formed in the region portion 201 as shown in FIG.

(3) Next, the drive mechanism 522 is controlled by the position controller, and moves the stage main body 521 to set the substrate 1 to the second processing position. As shown in FIG. 6, the second processing position is a position where the laser light 9 </ b> B irradiates a region portion 202 far from the infrared light receiving unit 100 in the nearby region 200.

(4) Then, the second laser oscillator 51B is operated by the control by the timing control unit, and continues the irradiation of the laser light 9B in the state of FIG. 6 (thermal processing step). Since the laser beam 9B is irradiated under thermal processing conditions, the region portion 202 is thermally processed, a through groove is formed in the region portion 202, and the through groove is combined with the through groove 21B, as shown in FIG. In addition, the through groove 2B is formed.

  As described above, in the laser processing method of the present embodiment, the laser light 9B is irradiated on the nearby region 200 under the thermal processing conditions, so that the processing can be performed with good workability. The region 201 close to the light receiving unit 100 is irradiated with the laser light 9A under the ablation processing conditions, so that it is possible to suppress the thermal influence on the infrared light receiving unit 100. Therefore, according to the laser processing method of this embodiment, the thermal influence on the anaerobic portion of the substrate can be made as small as possible, and the substrate 1 can be processed at high speed.

  Further, in the laser processing method of this embodiment, the first laser oscillator 51A is operated first to form the through groove 21B. Therefore, when the second laser oscillator 51B performs subsequent processing, the through groove 21B is It functions as a heat insulating space for the infrared light receiving unit 100. Therefore, even when the second laser oscillator 51B irradiates the laser beam 9B under the thermal processing condition, it is possible to suppress the thermal influence on the infrared light receiving unit 100. Therefore, according to the laser processing method of this embodiment, the thermal influence on the anaerobic portion of the substrate can be further reduced.

  Furthermore, according to the laser processing method of the present embodiment, the first laser oscillator 51A is an ultrashort pulse laser oscillator that outputs a laser beam having a pulse width of 100 femtoseconds to 100 picoseconds. Can be implemented well.

  Further, as described above, the laser processing apparatus 5 of the present embodiment includes the first laser oscillator 51A, the second laser oscillator 51B, the position control unit, and the timing control unit, and therefore the laser processing of the present embodiment. The method can be implemented reliably. In addition, since the first laser oscillator 51A is an ultrashort pulse laser oscillator that outputs a laser beam having a pulse width of 100 femtoseconds to 100 picoseconds, the ablation processing step in the laser processing method of the present embodiment can be favorably performed. .

[Second Embodiment]
The present embodiment is different from the first embodiment only in the timing at which the ablation process and the thermal process are performed. That is, in this embodiment, the ablation process is performed after the thermal process.

  Formation of the through groove 2B by the laser processing method of the present embodiment is performed as follows.

(1) First, the drive mechanism 522 is controlled by the position controller, and moves the stage body 521 to set the substrate 1 to the second processing position. As shown in FIG. 8, the second processing position is a position where the laser light 9 </ b> B irradiates a region portion 202 far from the infrared light receiving unit 100 in the near region 200.

(2) Next, the second laser oscillator 51B operates under the control of the timing control unit, and continues the irradiation of the laser light 9B in the state of FIG. 8 (thermal processing step). Since the laser beam 9B is irradiated under the thermal processing conditions, the region portion 202 is thermally processed, and the through groove 22B is formed in the region portion 202 as shown in FIG.

(3) Next, the drive mechanism 522 is controlled by the position controller, and moves the stage body 521 to set the substrate 1 to the first processing position. As shown in FIG. 9, the first processing position is a position where the laser light 9 </ b> A irradiates a region portion 201 close to the infrared light receiving unit 100 in the vicinity region 200.

(4) Then, the first laser oscillator 51A operates under the control of the timing control unit, and continues the irradiation of the laser light 9A in the state of FIG. 9 (ablation processing step). Since the laser beam 9A is irradiated under the ablation processing conditions, the region portion 201 is ablated, a through groove is formed in the region portion 201, and the through groove is combined with the through groove 22B, as shown in FIG. In addition, the through groove 2B is formed.

  Also by the laser processing method of this embodiment, the effect similar to the case of 1st Embodiment can be exhibited.

  However, in the laser processing method of this embodiment, since the thermal processing step is performed first, as shown in FIG. 9, the ablation processing is performed with the through groove 22B formed. Therefore, the surface area for evaporating or scattering the material of the substrate 1 in the ablation process is larger than that in the first embodiment. Therefore, according to the laser processing method of this embodiment, the workability of the ablation process can be improved, and the substrate 1 can be processed at a higher speed.

[Third Embodiment]
The present embodiment is different from the first embodiment only in the timing at which the ablation process and the thermal process are performed. That is, in this embodiment, the ablation process and the thermal process are performed simultaneously.

  Formation of the through groove 2B by the laser processing method of the present embodiment is performed as follows.

(1) First, the drive mechanism 522 is controlled by the position controller, and moves the stage main body 521 to set the substrate 1 to both the first processing position and the second processing position. In this setting, the irradiation position of the laser light 9A and / or the laser light 9B is moved to the processing position as necessary. As shown in FIG. 10, the first processing position is a position where the laser light 9 </ b> A irradiates a region portion 201 near the infrared light receiving unit 100 in the vicinity region 200. As shown in FIG. 10, the second processing position is a position where the laser light 9 </ b> B irradiates a region portion 202 far from the infrared light receiving unit 100 in the nearby region 200.

(2) Next, under the control of the timing control unit, the first laser oscillator 51A and the second laser oscillator 51B operate simultaneously, and the irradiation of the laser light 9A and the laser light 9B is continued in the state of FIG. Ablation process and thermal process). Since the laser beam 9A is irradiated under the ablation processing condition, the region portion 201 is ablated, a through groove is formed in the region portion 201, and the laser beam 9B is irradiated under the thermal processing condition, so that the region portion 202 is irradiated. Is heat-processed, and a through groove is formed in the region portion 202. As a result, both through grooves are combined to form a through groove 2B as shown in FIG.

  Also by the laser processing method of this embodiment, the effect similar to the case of 1st Embodiment can be exhibited.

  However, in the laser processing method of this embodiment, since the ablation processing step and the thermal processing step are performed simultaneously, the working time is shorter than in the first embodiment and the second embodiment. Therefore, according to the laser processing method of this embodiment, the substrate 1 can be processed at a higher speed.

  In addition, the anaerobic part in this invention is not restricted to the infrared rays light-receiving part 100, if it is a part which dislikes a thermal influence, ie, a part which is not preferable to receive a thermal influence.

  Further, the laser processing apparatus of the present invention is not limited to the one provided with two laser oscillators, and may be provided with one laser oscillator. In the case of a laser processing apparatus provided with one laser oscillator, a laser oscillator that can be set by arbitrarily switching between ablation processing conditions and thermal processing conditions may be used.

  The laser processing method of the present invention can greatly reduce the thermal influence on the anaerobic portion of the substrate as much as possible, and can process the substrate at a high speed, and thus has great industrial utility value.

  DESCRIPTION OF SYMBOLS 1 Substrate 5 Laser processing apparatus 51A 1st laser oscillator, 51B 2nd laser oscillator 200 Proximal area 201 (Near) area part 202 (Far) area part

Claims (4)

A laser processing method for forming a through-groove by irradiating a laser beam to a region near the anaerobic part to a substrate having an anaerobic part that dislikes thermal effects
Among the neighboring region, the the area part close to the bad heat portion to form a through groove by irradiating a laser beam ablation processing conditions, and ablation processing step,
Among the neighboring region, the region far part from the bad heat portion is irradiated with a laser beam to form a through groove in thermal processing conditions, the heat processing step,
And have a,
After the thermal processing step is performed, the ablation processing step is performed.
The laser processing method characterized by the above-mentioned. The ablation processing step is performed using an ultrashort pulse laser oscillator that outputs laser light having a pulse width of 100 femtoseconds to 100 picoseconds.
The laser processing method according to claim 1 . A laser processing apparatus for forming a through groove by irradiating a laser beam to a region near the anaerobic part with respect to a substrate having an anaerobic part that dislikes thermal effects
A first laser oscillator that outputs laser light so as to form a through groove under ablation processing conditions;
A second laser oscillator that outputs laser light so as to form a through groove under thermal processing conditions;
The irradiation position of the laser beam output from the first laser oscillator is set in a region portion close to the anaerobic portion in the neighboring region, and the irradiation of the laser beam output from the second laser oscillator is performed. A position control unit that sets a position in a region part far from the anaerobic part in the neighboring region; and
A timing control unit that controls the first laser oscillator and the second laser oscillator so that the first laser oscillator operates after the second laser oscillator operates ;
A laser processing apparatus comprising: The first laser oscillator is an ultrashort pulse laser oscillator that outputs laser light having a pulse width of 100 femtoseconds to 100 picoseconds.
The laser processing apparatus according to claim 3 .

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