JP5424113B2 - Processing apparatus and modulation mask used in processing apparatus - Google Patents

Description

  The present invention relates to a processing apparatus that forms at least one inclined portion on a workpiece by irradiating the workpiece including a non-processing portion with light emitted from a light source. The present invention also relates to a processing apparatus for forming at least one tapered tapered hole having a through portion or a bottom portion and a tapered portion on a workpiece by irradiating the workpiece with light emitted from a light source. . The present invention also relates to a modulation mask used in a processing apparatus.

  In recent years, parts (workpieces) for parts used in electronic devices or the like are required to be processed into various shapes with high accuracy. As an example of the required shape, it is possible to form an inclined portion on the workpiece. For example, the nozzle of an inkjet head used in a printer or the like has a shape that is inclined (tapered) so that the tip of the nozzle is thinner than the base end in order to obtain good ink ejection performance. Is required.

  FIG. 20 shows a processing apparatus 100 in a conventional inkjet head nozzle forming method. On the stage 109 of the processing apparatus 100, a nozzle forming sheet 108 made of a resin plate such as polyimide and having nozzles formed by laser processing is placed. The pulsed laser light emitted from the laser light source 102 passes through the illumination optical system 103 that makes the light intensity distribution uniform, and then enters the mask 104. The mask 104 is formed by stacking a quartz glass layer 105 that transmits light and a light shielding layer 106 made of a metal that shields light, and the light shielding layer 106 has a circular opening at the center thereof. Part 106a. Therefore, of the laser light incident on the mask 104, only the laser light incident on the region corresponding to the opening 106a of the light shielding layer 106 is transmitted through the mask 104, and other light is transmitted by the light shielding layer 106 of the mask 104. Shielded. The laser beam that has passed through the mask 104 is imaged on the nozzle forming sheet 108 by the imaging optical system 107. The light imaged and irradiated on the nozzle forming sheet 108 has a circular pattern corresponding to the opening 106a of the light shielding layer 106. Therefore, the nozzle forming sheet 108 is processed into a circular shape. Thereby, the nozzle 110 having a tapered shape is manufactured.

  As shown in FIG. 21, there is a relationship between the taper angle of the nozzle 110 manufactured by laser processing and the energy density of the irradiated laser light, in which the taper angle increases as the irradiation energy density decreases. Are known. By utilizing this relationship, it is possible to adjust the energy density of the irradiated laser light to form the tapered portion 110b having a desired angle. For example, Patent Document 1 discloses an apparatus that forms the nozzle 110 by adjusting the energy density of the irradiated laser light so as to form a tapered portion 110b having a predetermined angle.

JP 2002-67333 A

  However, in the nozzle forming method as described above, the ablation rate (the depth of the workpiece removed by one pulsed light irradiation) is reduced by reducing the irradiation energy density in order to obtain a large taper angle. descend. For this reason, even when processing a tapered hole having the same depth, in order to obtain a large taper angle, it is necessary to increase the number of times of laser light irradiation, and thereby the processing time required to form the tapered hole is increased. The problem of lengthening arises. In addition, since the life of the laser light source 102 is determined by the number of times the laser light is emitted, increasing the number of times of irradiating the workpiece with the laser light shortens the life of the laser light source 102, thereby changing the replacement frequency of the laser light source 101. There is also a problem that increases. Furthermore, if the irradiation energy density is reduced in order to obtain a large taper angle, there arises a problem that the variation in the inner diameter of the tip portion 110c of the manufactured nozzle 110 increases.

  The present invention has been made in consideration of such points, and an object of the present invention is to provide a processing apparatus capable of forming an inclined portion on a workpiece with high accuracy in a short processing time. Another object of the present invention is to provide a modulation mask used in the processing apparatus.

A first aspect of the present invention is a light source that emits light in a processing apparatus that forms at least one inclined portion on a workpiece by irradiating the workpiece including a non-processing portion with light emitted from the light source. A modulation mask that is provided on the emission side of the light source and that modulates and emits light from the light source; and an image that is provided on the emission side of the modulation mask and is modulated by the modulation mask to form a workpiece An imaging optical system that forms an inclined portion on the workpiece, and the modulation mask includes a modulation mask inclined portion that phase-modulates light irradiated to the inclined portion of the workpiece, and A modulation mask shielding part corresponding to a non-working part of the workpiece, and the modulation mask inclination part is composed of a plurality of phase modulation unit regions, and is formed by the modulation mask inclination part. The phase-modulated light emitted from the imaging optics A light intensity distribution based on the phase modulation unit region is generated on the imaging surface of the image forming unit, and the modulation mask shielding unit includes a light shielding layer for shielding light, and the phase modulation unit region is imaged by the imaging optical system. The phase modulation unit conversion region converted into a surface is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system, and the radius R of the point image distribution range of the imaging optical system is the center wavelength of light. Is defined as R = 0.61λ / NA, and the phase modulation unit region includes a first phase modulation amount having a first phase modulation amount. A unit region and a second phase modulation unit region having a second phase modulation amount, wherein the occupation ratio of the first phase modulation unit region in the modulation mask inclined portion is Tp ₁ , and the occupation of the second phase modulation unit region is when the rate and Tp _2, put the modulation mask inclined portion Distribution of tp ₁ and tp ₂ is characterized by being distributed so that increases {absolute value of (Tp 1 _{-Tp 2)}} with increasing distance from the area adjacent to the modulating mask shielding portion of the modulating mask inclined portion It is a processing device.
According to 1st this invention, it can prevent that the light which has the intensity | strength which can process a workpiece is irradiated to the non-processed part of a workpiece. This can reliably prevent the non-processed portion from being processed.
In addition, according to the first aspect of the present invention, the intensity of light applied to the inclined portion of the workpiece can be adjusted so as to continuously increase as the distance from the non-processing portion of the workpiece is increased. As a result, the inclined portion can be formed on the workpiece with high accuracy in a short processing time.

  In the first aspect of the present invention, at least one inclined portion and a maximum processed portion located on the bottom side of the inclined portion may be formed on the workpiece by processing with a processing apparatus. In this case, the modulation mask includes a modulation mask inclination portion that phase-modulates light applied to the inclination portion, a modulation mask shielding portion that is adjacent to one side of each modulation mask inclination portion, and corresponds to the non-processed portion. And a modulation mask transmission portion corresponding to the maximum processing portion adjacent to the other side of each modulation mask inclined portion.

In the first aspect of the present invention, the modulation mask transmission unit includes a plurality of phase modulation unit regions, and light emitted after being phase-modulated by the modulation mask transmission unit is applied to the imaging surface of the imaging optical system. A light intensity distribution based on a unit region may be generated. In this case, the occupation ratio of the first phase modulation unit area in the modulation mask transmission part is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation of the first phase modulation unit area in the modulation mask inclined part is When the rate is Tp ₁ and the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Has been.

The second aspect of the present invention is a process for forming at least one tapered tapered hole having a through portion or a bottom portion and a tapered portion on a workpiece by irradiating the workpiece with light emitted from a light source. In the apparatus, a light source that emits light, a modulation mask that is provided on the emission side of the light source and that modulates and emits light from the light source, and light that is provided on the emission side of the modulation mask and modulated by the modulation mask And an imaging optical system that forms a tapered hole in the workpiece, and the modulation mask applies light to the penetrating portion or bottom portion of the tapered hole. Corresponding modulation mask transmission part, modulation mask tilt part for phase modulation of light irradiated to the taper part of the taper hole located at the periphery of each modulation mask transmission part, and modulation positioned at the periphery of each modulation mask tilt part A mask shielding part, The modulation mask tilt part is composed of a plurality of phase modulation unit areas, and light emitted after being phase-modulated by the modulation mask tilt part is distributed on the imaging plane of the imaging optical system based on the phase modulation unit areas. The modulation mask shielding unit includes a light shielding layer that shields light, and the phase modulation unit conversion region obtained by converting the phase modulation unit region into an imaging surface of the imaging optical system is the imaging optical The radius R of the point image distribution range of the imaging optical system is λ as the center wavelength of the light, and the numerical aperture on the exit side of the imaging optical system is smaller than the radius of the point image distribution range of the system. When NA is defined, R = 0.61λ / NA, and the phase modulation unit region includes a first phase modulation unit region having a first phase modulation amount and a second phase having a second phase modulation amount. A modulation unit region, and the modulation mask tilt Tp 1 occupancy of the first phase modulation unit area _in, when the occupation rate of the second phase modulation unit areas and Tp _2, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, among the modulation mask inclined portion The processing apparatus is characterized in that {Absolute value of (Tp ₁ −Tp ₂ )} is distributed so as to increase from a region adjacent to the modulation mask shielding portion to a region adjacent to the modulation mask transmission portion. is there.
According to the second aspect of the present invention, it is possible to prevent the portion of the workpiece that is not formed with the tapered hole from being irradiated with light having an intensity capable of processing the workpiece. As a result, it is possible to reliably prevent the portion where the tapered hole is not formed from being processed.
According to the second aspect of the present invention, the intensity of light applied to the inclined portion of the workpiece is adjusted so as to continuously increase from the non-working portion of the workpiece toward the penetrating portion or the bottom portion. be able to. This makes it possible to form a tapered hole in the workpiece with high accuracy in a short processing time.

In the second aspect of the present invention, the modulation mask transmission section includes a plurality of phase modulation unit regions, and light emitted after being phase-modulated by the modulation mask transmission section is formed on the imaging surface of the imaging optical system. A light intensity distribution based on a unit region may be generated. In this case, the occupation ratio of the first phase modulation unit area in the modulation mask transmission part is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation of the first phase modulation unit area in the modulation mask inclined part is When the rate is Tp ₁ and the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Has been.

  In the first and second aspects of the present invention, the workpiece may include a basic resin and a filler added to the basic resin. In this case, the basic resin and the filler are removed by the light irradiated through the modulation mask, whereby the workpiece is processed.

  In the first and second aspects of the present invention, the first phase modulation amount in the first phase modulation unit region and the second phase modulation amount in the second phase modulation unit region differ by an odd multiple of 180 degrees. May be.

  In the first and second aspects of the present invention, the modulation mask shielding portion may comprise a light shielding layer having a light transmittance of zero.

According to a third aspect of the present invention, there is provided a modulation mask incorporated in a processing apparatus for forming at least one inclined portion on a workpiece by irradiating the workpiece including a non-processing portion with light emitted from a light source. The processing apparatus includes a light source that emits light, a modulation mask that is provided on the emission side of the light source, modulates and emits light from the light source, and is provided on the emission side of the modulation mask and is modulated by the modulation mask. And an imaging optical system that forms an inclined portion on the workpiece, forms an inclined portion on the workpiece, and the modulation mask applies the light irradiated to the inclined portion of the workpiece. A modulation mask inclined portion that performs phase modulation; and a modulation mask shielding portion that is adjacent to each modulation mask inclined portion and corresponds to a non-processed portion of the workpiece. The modulation mask inclined portion includes a plurality of phase modulation components. Consists of unit area and phase by modulation mask inclined part The adjusted and emitted light generates a light intensity distribution based on the phase modulation unit region on the imaging surface of the imaging optical system, and the modulation mask shielding unit includes a light shielding layer that shields light, The phase modulation unit conversion region obtained by converting the phase modulation unit region to the imaging surface of the imaging optical system is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system, The radius R of the point image distribution range is defined as R = 0.61λ / NA where λ is the center wavelength of light and NA is the numerical aperture on the exit side of the imaging optical system, and the phase modulation unit region is The first phase modulation unit region having the first phase modulation amount and the second phase modulation unit region having the second phase modulation amount, and occupying the first phase modulation unit region in the modulation mask inclined portion the rate Tp _1, the occupation ratio of the second phase modulation unit areas Tp To time, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, increase {absolute value of (Tp 1 _{-Tp 2)}} with increasing distance from the area adjacent to the modulating mask shielding portion of the modulating mask inclined portion and It is a modulation mask characterized by being distributed as follows.
According to the third aspect of the present invention, it is possible to prevent the non-processed portion of the workpiece from being irradiated with light having an intensity capable of processing the workpiece. This can reliably prevent the non-processed portion from being processed.
Further, according to the third aspect of the present invention, the intensity of light applied to the inclined portion of the workpiece can be adjusted so as to increase continuously as the distance from the non-processing portion of the workpiece increases. As a result, the inclined portion can be formed on the workpiece with high accuracy in a short processing time.

  In the third aspect of the present invention, at least one inclined portion and a maximum processed portion located on the bottom side of the inclined portion may be formed on the workpiece by the processing by the processing apparatus. In this case, the modulation mask incorporated in the processing apparatus is adjacent to one side of each modulation mask inclined portion, which corresponds to the non-processed portion, and a modulation mask inclined portion for phase-modulating light irradiated to the inclined portion. And a modulation mask transmission portion corresponding to the maximum processing portion adjacent to the other side of each modulation mask inclined portion.

In the third aspect of the present invention, the modulation mask transmission unit includes a plurality of phase modulation unit regions, and light emitted after being phase-modulated by the modulation mask transmission unit is applied to the imaging surface of the imaging optical system. A light intensity distribution based on a unit region may be generated. In this case, the occupation ratio of the first phase modulation unit area in the modulation mask transmission part is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation of the first phase modulation unit area in the modulation mask inclined part is When the rate is Tp ₁ and the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Has been.

The fourth aspect of the present invention is a process for forming at least one tapered tapered hole having a through portion or a bottom portion and a tapered portion on a workpiece by irradiating the workpiece with light emitted from a light source. In the modulation mask incorporated in the apparatus, the processing apparatus includes: a light source that emits light; a modulation mask that is provided on an emission side of the light source and that modulates and emits light from the light source; and an emission side of the modulation mask And an imaging optical system that forms an image of light modulated by the modulation mask and irradiates the work piece to form a tapered hole in the work piece. A modulation mask transmission part corresponding to the light irradiated to the penetrating part or the bottom part, a modulation mask inclined part positioned at the periphery of each modulation mask transmission part and phase-modulating the light irradiated to the taper part of the taper hole; Each modulation mask slope A modulation mask shielding portion positioned at an edge, and the modulation mask tilt portion is composed of a plurality of phase modulation unit regions, and light emitted after being phase-modulated by the modulation mask tilt portion is transmitted from the imaging optical system. A light intensity distribution based on the phase modulation unit region is generated on an imaging surface, and the modulation mask shielding unit includes a light shielding layer that shields light, and the phase modulation unit region is formed on the imaging surface of the imaging optical system. The phase modulation unit conversion region converted into is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system, and the radius R of the point image distribution range of the imaging optical system is the center wavelength of light. λ, where NA is the numerical aperture on the exit side of the imaging optical system, R is defined as 0.61λ / NA, and the phase modulation unit region is a first phase modulation unit having a first phase modulation amount Region and second phase modulation having second phase modulation amount And position region consists, the occupancy rate of the first phase modulation unit area in the modulation mask inclined portion Tp _1, when the occupation rate of the second phase modulation unit areas and Tp _2, Tp ₁ and in the modulation mask inclined portion The distribution of Tp ₂ is such that {absolute value of (Tp ₁ −Tp ₂ )} increases from a region adjacent to the modulation mask shielding part to a region adjacent to the modulation mask transmission part in the modulation mask inclined part. It is a modulation mask characterized by being distributed.
According to the fourth aspect of the present invention, it is possible to prevent the portion of the workpiece that is not formed with the tapered hole from being irradiated with light having an intensity capable of processing the workpiece. As a result, it is possible to reliably prevent the portion where the tapered hole is not formed from being processed.
According to the fourth aspect of the present invention, the intensity of light applied to the inclined portion of the workpiece is adjusted so as to continuously increase from the non-working portion of the workpiece toward the penetrating portion or the bottom portion. be able to. This makes it possible to form a tapered hole in the workpiece with high accuracy in a short processing time.

In the fourth aspect of the present invention, the modulation mask transmission section includes a plurality of phase modulation unit areas, and the phase modulated light emitted from the modulation mask transmission section is emitted to the imaging surface of the imaging optical system. A light intensity distribution based on a unit region may be generated. In this case, the occupation ratio of the first phase modulation unit area in the modulation mask transmission part is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation of the first phase modulation unit area in the modulation mask inclined part is When the rate is Tp ₁ and the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Has been.

  In the third and fourth aspects of the present invention, the workpiece may include a basic resin and a filler added to the basic resin. In this case, the basic resin and the filler are removed by the light irradiated through the modulation mask, whereby the workpiece is processed.

  In the third and fourth aspects of the present invention, the first phase modulation amount in the first phase modulation unit region and the second phase modulation amount in the second phase modulation unit region differ by an odd multiple of 180 degrees. May be.

  In the third and fourth aspects of the present invention, the modulation mask shielding part may comprise a light shielding layer having a light transmittance of zero.

  ADVANTAGE OF THE INVENTION According to this invention, the processing apparatus which forms an inclination part in a workpiece accurately with a short processing time can be provided. According to the present invention, a modulation mask used in the processing apparatus can be provided.

FIG. 1 shows a processing apparatus according to the present invention. FIG. 2 is a plan view showing the emission side of the modulation mask in the first embodiment of the present invention, and FIG. 2B is a longitudinal sectional view of the modulation mask of FIG. 2A viewed from the IIb-IIb direction. . 3A is an enlarged view showing a region surrounded by a thick frame in the modulation mask shown in FIG. 2A, and FIG. 3B shows each phase modulation unit region in FIG. 3A. FIG. 4A is a diagram showing an imaging plane of light emitted from the imaging optical system with respect to the workpiece, FIG. 4B is a diagram showing a point spread function on the imaging plane, and FIG. FIG. 4C is a diagram showing the relationship between the point spread function on the imaging plane and the phase modulation unit area in the modulation mask inclined part and modulation mask transmission part, and FIG. The figure which shows the concept of the light intensity in. FIG. 5A is a diagram showing a pupil function in the imaging optical system, and FIG. 5B is a diagram showing a point image distribution function in the imaging plane. FIG. 6 is a diagram illustrating a modulation mask design flowchart. FIG. 7A is a longitudinal sectional view showing a tapered hole formed in the workpiece in the first embodiment of the present invention, and FIG. 7B shows the tapered hole formed in the workpiece. FIG. FIG. 8A is a diagram showing the relationship between the energy density of light irradiated on the workpiece and the workpiece processed by this in the first comparative embodiment, and FIG. The figure which shows the relationship between the energy density of the light irradiated to a workpiece, and the workpiece processed by this in the 1st Embodiment of this invention. FIG. 9 is a plan view showing the emission side of the modulation mask in the second comparative embodiment. FIG. 10A is an enlarged view showing a region surrounded by a thick frame in the modulation mask shown in FIG. 9, and FIG. 10B shows each amplitude modulation unit region in FIG. 10A. FIG. FIG. 11 is a longitudinal sectional view showing a modified example of the tapered hole formed in the workpiece. FIG. 12A is a plan view showing the emission side of the modulation mask according to the second embodiment of the present invention, and FIG. 12B shows the modulation mask of FIG. 12A from the XIIb-XIIb direction. Viewed longitudinal section. FIG. 13A is a plan view showing a workpiece in the second embodiment of the present invention, and FIG. 13B shows the workpiece of FIG. 13A viewed from the XIIIb-XIIIb direction. FIG. FIG. 14A is a plan view showing the emission side of the modulation mask in the modification of the second embodiment of the present invention, and FIG. 14B shows the modulation mask of FIG. The longitudinal cross-sectional view seen from the XIVb direction. FIG. 15A is a plan view showing a workpiece in a modification of the second embodiment of the present invention, and FIG. 15B shows the workpiece of FIG. 15A as XVb-XVb. The longitudinal cross-sectional view seen from the direction. 16A is a longitudinal sectional view showing the shape of a tapered hole formed in the workpiece, FIG. 16B is a diagram showing the intensity distribution I of the laser beam irradiated on the workpiece, FIG. (C) is a top view which shows the taper hole formed in the to-be-processed object. FIG. 17A is a plan view showing the modulation mask in the first embodiment, and FIG. 17B is a diagram showing the intensity of light emitted from the modulation mask shown in FIG. 18A shows the shape of the second phase modulation unit area of the phase modulation unit area, and FIG. 18B shows the dimensional error of the second phase modulation unit area and the second phase modulation unit area. The figure which shows the relationship with the intensity | strength of the light modulated by the phase modulation unit area | region containing. FIG. 19A is a plan view showing a modulation mask in Comparative Example 1, and FIG. 19B is a diagram showing the intensity of light emitted from the modulation mask shown in FIG. FIG. 20 is a diagram showing a conventional processing apparatus. FIG. 21 is a diagram showing the relationship between the inclination and angle of the tapered hole and the irradiation energy.

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

(Workpiece and tapered hole)
First, the workpiece 18 processed by the processing apparatus 10 and the tapered hole 20 formed in the workpiece 18 will be described with reference to FIG. FIG. 7A is a longitudinal sectional view showing a tapered hole 20 formed in the workpiece 18, and FIG. 7B is a plan view showing the tapered hole 20 formed in the workpiece 18. .

  As shown in FIGS. 7A and 7B, the workpiece 18 has a flat plate shape, and includes a basic resin 18d and a filler 18e added to the basic resin 18d. 7A and 7B, the tapered hole 20 formed in the workpiece 18 includes a through portion 20a and a through portion 20a from the proximal end portion 20d of the tapered hole 20 toward the distal end portion 20c. Has a tapered portion 20b having a surface inclined so as to be tapered. Here, the inclination angle of the tapered portion 20b is an angle φ as shown in FIG. 7A shows an example in which the filler 18e is added only to the upper surface side of the workpiece 18. However, the present invention is not limited to this, and the filler 18e is not provided on the lower surface side of the workpiece 18. It may be added. Further, the filler 18e may be added throughout the workpiece 18.

  As the material of the basic resin 18d of the workpiece 18, a material having good workability and physical stability is used. For example, when the workpiece 18 is processed to manufacture an inkjet head nozzle, polyimide or the like is used as the basic resin 18d. In addition, as the filler 18e added to the basic resin 18d, a material capable of improving the slipperiness of the workpiece 18 is used, for example, silica or calcium carbonate particles. By adding such a filler 18e to the basic resin 18d, it is possible to improve the slippage between the workpieces 18, thereby improving workability when forming the tapered hole 20 in the workpiece 18. Can be made.

  In the present embodiment, the portion of the workpiece 18 where the through portion 20a of the tapered hole 20 is formed is the maximum processed portion 18a, and the portion where the tapered portion 20b of the tapered hole is formed is an inclined portion. The portion where the tapered hole 20 is not formed is a non-processed portion 18c (see FIG. 7B). The maximum processed portion 18 a is a portion of the workpiece 18 that is processed most deeply by the processing device 10, and the non-processed portion 18 c is processed by the processing device 10 of the workpiece 18. This is an undesirable part.

(Processing equipment)
Next, the entire processing apparatus 10 will be described with reference to FIG. FIG. 1 is a diagram showing a processing apparatus 10 according to the first embodiment of the present invention. As shown in FIG. 1, the processing apparatus 10 is provided on a processing table 19 on which a workpiece 18 is placed, a mask illumination system 11 that emits light, and an exit side of the mask illumination system 11. A modulation mask 24 that modulates and emits light from the light source, and an output side of the modulation mask 24 that forms an image of the light modulated by the modulation mask 24 and irradiates the workpiece 18. And an imaging optical system 17 that forms at least one tapered hole 20 having a through portion 20a and a tapered portion 20b.

  Among these, the mask illumination system 11 includes a laser light source 12 that emits pulsed laser light, and an illumination optical system 13 that uniformizes the light intensity distribution of the laser light from the laser light source 12. Specifically, the laser light source 12 is composed of a XeCl excimer laser light source 12 that supplies light having a wavelength of 308 nm for processing the workpiece 18 by ablation. The illumination optical system 13 equalizes the in-plane intensity distribution of the light from the laser light source 12, and also uniformizes the incident angle distribution of the light incident on the modulation mask 24 from the illumination optical system 13. An eye lens (not shown) and a condenser optical system (not shown) are included.

  As described above, the modulation mask 24 is provided on the emission side of the mask illumination system 11 and modulates and emits the light from the mask illumination system 11. Details will be described later.

  The laser light modulated by the modulation mask 24 is incident on the imaging optical system 17 provided on the emission side of the modulation mask 24. The imaging optical system 17 forms an image of the light modulated by the modulation mask 24 and irradiates the workpiece 18. As shown in FIG. 1, the convex lens 17a, the convex lens 17b, the both lenses 17a, And an aperture stop 17c provided between 17b. The size of the aperture 17k of the aperture stop 17c substantially corresponds to the image-side numerical aperture NA of the imaging optical system 17. As will be described later, the size of the opening 17k is set so as to generate a required light intensity distribution in the workpiece 18.

  The laser beam imaged by the imaging optical system 17 is irradiated to the workpiece 18. The workpiece 18 is made of a material that is easily ablated by a laser beam having a wavelength of 308 nm, and is made of a polymer material such as polyimide, for example. The workpiece 18 is disposed on a surface optically conjugate with the modulation mask 24, that is, an imaging surface 17 f described later of the imaging optical system 17.

(Modulation mask)
Next, the modulation mask 24 in the present embodiment will be described with reference to FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b). 2A is a plan view showing the emission side of the modulation mask 24, and FIG. 2B is a longitudinal sectional view of the modulation mask 24 of FIG. 2A viewed from the IIb-IIb direction. In the present embodiment, the modulation mask 24 has a flat plate shape, and is arranged so that the plane portion thereof is orthogonal to the incident and exit directions of the laser beam. 3A is an enlarged view showing a region surrounded by a thick frame in the modulation mask 24 shown in FIG. 2A, and FIG. 3B shows each phase of FIG. 3A. It is a longitudinal cross-sectional view which shows a modulation unit area | region.

  First, the structure of the modulation mask 24 when viewed from the emission side of the modulation mask 24 will be described with reference to FIG. As shown in FIG. 2A, the modulation mask 24 is positioned at the periphery of the modulation mask transmission part 24a for phase-modulating the light irradiated to the penetrating part 20a of the taper hole 20, and the modulation mask transmission part 24a. A modulation mask inclined portion 24b that phase-modulates light irradiated to the tapered portion 20b of the hole 20, and a modulation mask shielding portion 24c that is located at the periphery of the modulation mask inclined portion 24b and corresponds to the non-processed portion 18c of the workpiece 18 It consists of. Further, as shown in FIG. 2B, each of the modulation mask transmission part 24a and the modulation mask inclination part 24b includes a plurality of phase modulation unit regions 24e. On the other hand, as shown in FIG. 2B, the modulation mask shield 24c includes a light shield layer 27 that shields light. The modulation mask 24 is provided with a number of modulation mask transmission parts 24a and modulation mask inclined parts 24b corresponding to the number of tapered holes 20 formed in the workpiece 18, respectively, but in this embodiment, The case where one modulation mask transmission part 24a and one modulation mask inclination part 24b are provided in the modulation mask 24 will be described.

Next, the phase modulation unit region 24e will be described in detail. Of the modulation mask 24, for example, the modulation mask inclined portion 24b has phase modulation unit regions 24e _{1 to} 24e ₅ as shown in FIG. Further, an amplitude modulation unit conversion region obtained by converting these phase modulation unit regions 24e _{1 to} 24e ₅ into an imaging surface 17f described later of the imaging optical system 17 is based on a radius R of a point image distribution range described later of the imaging optical system 17. Also, the modulation mask 24 is designed to be small in at least one direction.

Further, as shown in FIG. 3A, each of the phase modulation unit regions 24e _{1 to} 24e ₅ of the modulation mask inclined portion 24b has a first phase modulation unit region 25a _{1 to} 25a ₅ having a first phase modulation amount, respectively. And second phase modulation unit regions 25b _{1 to} 25b ₅ having a second phase modulation amount. Here, as is clear from FIG. 3 (a), in each of the phase modulation unit regions 24e _{1 to} 24e ₅ of the modulation mask inclined part 24b, the occupancy rate of each of the first phase modulation unit regions 25a _{1 to} 25a ₅ (each phase modulation unit) in the first phase modulation unit region _25a 1 ～25A area ratio of _5), and the occupancy of the second phase modulation unit region _25b 1 _{~25b 5} (the respective phase modulating unit region _24e 1 ～24E ₅ in the area _24e 1 ～24E ₅ The area ratios of the second phase modulation unit regions 25b _{1 to} 25b ₅ are different from each other. For example, the first phase occupancy rate of the modulation unit region 25a ₁ of the phase modulation unit region 24e ₁ is 0.90, occupancy of the second phase modulation unit region 25b ₁ is 0.10. The occupancy rate of the first phase modulation unit region 25a ₅ in the phase modulation unit area 24e ₅ is 0.55, the occupancy of the second phase modulation unit region 25b ₅ is 0.45.

Next, the structure of each of the phase modulation unit regions 24e _{1 to} 24e ₅ of the modulation mask inclined portion 24b will be described in detail with reference to FIG. FIG. 3B is a longitudinal sectional view showing each of the phase modulation unit regions 24e _{1 to} 24e ₅ . As shown in FIG. 3B, each of the phase modulation unit regions 24e _{1 to} 24e ₅ of the modulation mask 24 is formed from a transmissive substrate, for example, a quartz glass 26 having a refractive index n, having irregularities on its surface. ing. Here, the height of the quartz glass 26 in the region corresponding to the first phase modulation unit region _25a 1 _{~25a 5} out of the respective phase modulating unit region _24e 1 _{~24e 5,} among the phase modulation unit area _24e 1 _{~24e 5} A difference from the height of the quartz glass 26 in the region corresponding to the second phase modulation unit regions 25b _{1 to} 25b ₅ is Δh. In this case, when the refractive index of air is 1, the optical distance of the respective phase modulating unit region _24e 1 _{~24e 5,} to the exit surface 24h from the incident surface of the modulation mask 24 in the first phase modulation unit region _25a 1 _{~25a 5} And the optical distance from the incident surface of the modulation mask 24 to the exit surface 24h in the second phase modulation unit regions 25b _{1 to} 25b ₅ is Δh × (n−1).

In the present embodiment, the optical distance difference Δh × (n−1) is an odd multiple of {λ / 2}, that is, the phase modulation amount in the first phase modulation unit regions 25a _{1 to} 25a ₅ . Δh is set so that the difference between the phase modulation amounts in the second phase modulation unit regions 25b _{1 to} 25b ₅ is an odd multiple of 180 degrees. For example, when the center wavelength λ of the laser light emitted from the mask illumination system 11 is 308 nm and the refractive index n of the quartz glass 26 forming the phase modulation unit regions 24e _{1 to} 24e ₅ is 1.49, Δh is 317 nm. The phase modulation unit regions 24e _{1 to} 24e ₅ are designed so as to be.

Although described with reference to FIG. 3 (a) (b) for each phase modulation unit area _24e 1 _{~24e 5} modulation mask inclined portion 24b, also in the modulation mask transmission unit 24a, each of the phase modulation unit The modulation mask 24 is designed so that the phase modulation unit conversion region obtained by converting the region 24e into the imaging surface 17f of the imaging optical system 17 is smaller in at least one direction than the radius R of the point image distribution range of the imaging optical system 17. Has been. Each phase modulation unit region 24e in the modulation mask transmission unit 24a also includes a first phase modulation unit region 25a having a first phase modulation amount and a second phase modulation unit region 25b having a second phase modulation amount. Become.

Next, the occupation ratio of the first phase modulation unit region 25a and the occupation ratio of the second phase modulation unit region 25b in the modulation mask transmission unit 24a and the modulation mask inclination unit 24b will be described. In the present embodiment, the occupation ratio of the first phase modulation unit region 25a in the modulation mask transmission section 24a is Cp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Cp ₂ . Similarly, the occupation ratio of the first phase modulation unit region 25a in the modulation mask inclined portion 24b is Tp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Tp ₂ . At this time, the modulation mask 24 is designed so that the relationship {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Further, the distribution of Tp ₁ and Tp _{2 in} the modulation mask inclined portion 24b is from the region adjacent to the modulation mask shielding portion 24c in the modulation mask inclined portion 24b toward the region adjacent to the modulation mask transmitting portion 24a {(Tp ₁ are distributed such that the absolute value of -tp _2)} is increased.

  Next, the modulation mask shielding part 24c will be described in detail. As described above, the modulation mask shielding part 24c includes the light shielding layer 27 that shields light. For this reason, most of the light incident on the modulation mask shielding part 24c out of the light incident on the modulation mask 24 from the mask illumination system 11 is shielded by the light shielding layer 27 of the modulation mask shielding part 24c. Thereby, it is possible to prevent the light incident on the modulation mask 24 from the mask illumination system 11 from being transmitted through the modulation mask shielding part 24c and irradiating the non-processed part 18c of the workpiece 18, thereby It is possible to reliably prevent the non-processed portion 18c of the workpiece 18 from being processed.

  The light transmittance of the light shielding layer 27 of the modulation mask shielding part 24c is such that the intensity of light transmitted through the modulation mask shielding part 24c and irradiated to the non-working part 18c of the workpiece 18 is equal to the ablation threshold value of the workpiece 18. It is appropriately selected so as not to exceed. For example, the light transmittance of the light shielding layer 27 is 0.00001 or less, preferably 0. As a material of the light shielding layer 27, a material capable of realizing a desired light transmittance can be appropriately used. For example, various light shielding materials such as chromium, aluminum, silicon oxide, or a dielectric multilayer film are used. Can do.

(Generation principle of light intensity distribution)
Next, referring to FIG. 4 and FIG. 5, the light that is phase-modulated by the modulation mask transmission unit 24a and the modulation mask tilting unit 24b and is emitted is based on the phase modulation unit region 24e on the imaging surface of the imaging optical system 17. The principle of generating the light intensity distribution will be described. Here, FIG. 4A is a diagram showing the imaging optical system 17, and FIG. 4B is a diagram showing a point spread function on the imaging surface 17f. FIG. 4C is a diagram showing the relationship between the point spread function on the imaging plane 17f and the phase modulation unit region 24e in the modulation mask transmission part 24a and the modulation mask tilt part 24b of the modulation mask 24. (D) is a figure which shows the concept of the light intensity in the point spread function of the image plane 17f. FIG. 5A is a diagram showing a pupil function in the imaging optical system 17, and FIG. 5B is a diagram showing a point spread function on the imaging surface 17f.

ここで、ｄはパルス状のレーザ光を被加工物１８に一回照射したときのアブレーションレート、αは被加工物１８の光吸収率、Ｉはレーザ光のエネルギー密度、Ｉ_ｔｈは被加工物１８におけるアブレーション発生閾値を示す。 First, the relationship between the intensity of laser light and the ablation depth will be described. In general, the relational expression of [Equation 1] holds between the intensity of the laser beam irradiated to the workpiece 18 and the depth (ablation rate) of the portion of the workpiece 18 that is removed by ablation. It has been known.

Here, d is the ablation rate when the workpiece 18 is irradiated with pulsed laser light once, α is the light absorption rate of the workpiece 18, I is the energy density of the laser beam, and I _th is the workpiece. 18 shows the ablation occurrence threshold value in FIG.

  As is apparent from [Equation 1], the ablation rate d depends on the energy density I of the laser beam. In addition, when laser light irradiation is repeated a plurality of times, it is known that the total depth of the portion of the workpiece 18 that is removed by laser light irradiation is proportional to the number of times of laser light irradiation. Therefore, by arbitrarily setting the energy density I of the laser light irradiated to the workpiece 18 according to the location of the workpiece 18, the workpiece 18 can be processed into an arbitrary shape.

When the energy density I of the laser beam exceeds a predetermined value, for example, I _upper , the laser irradiated on the workpiece 18 by the scattered matter generated when a part of the workpiece 18 is removed by ablation. The phenomenon that light is absorbed and scattered occurs. In this case, the energy of the laser beam applied to the workpiece 18 is used for the ablation of the workpiece 18 and the absorption / scattering of the laser beam by the scattered matter. For this reason, the energy density of the laser beam is used. Even if I is increased, the ablation rate d becomes saturated at a certain value. That is, the relational expression of [Equation 1] does not hold. Therefore, in the present embodiment, the energy density I of the laser light is set so as not to exceed I _upper .

  Next, the relationship between the object plane (modulation mask 24) and the imaging plane 17f (workpiece 18) in the imaging optical system 17 will be described.

ここで、＊はコンボリューション（たたみ込み積分）を表す。 The relationship between the object plane distribution and the imaging plane distribution in the imaging optical system 17 can be generally handled by Fourier imaging theory. When the coherence factor is about 0.5 or less, it can be approximated as coherent imaging. In this case, the complex amplitude distribution U (x, y) on the imaging plane, that is, the workpiece 18, is represented by the following [Equation 2], the complex amplitude transmittance distribution T (x, y) of the modulation mask 24. And the convolution integral of the complex amplitude point spread function ASF (x, y) of the imaging optical system 17

Here, * represents convolution (convolution integration).

ここで、ｒは以下の〔数４〕により表される関数である。また、Ｊ_１はベッセル関数、λは光の波長、ＮＡは結像光学系１７の結像側開口数を表す。

The above point spread function ASF (x, y) is given by Fourier transform of the pupil function of the imaging optical system 17. In this case, if the pupil is circular and has no aberration, a well-known Airy pattern is obtained ([Equation 3]).

Here, r is a function represented by the following [Equation 4]. J ₁ is a Bessel function, λ is the wavelength of light, and NA is the imaging-side numerical aperture of the imaging optical system 17.

  Next, the point spread function ASF (x, y) of the imaging optical system 17 will be described. 4A is a diagram showing the imaging optical system 17, and FIG. 4B shows a point spread function ASF (x, y) of the imaging optical system 17. In FIG. 4B, the horizontal axis corresponds to the position on the image plane 17f. A cylindrical shape 17e having a diameter 2R indicated by a broken line in FIG. 4B is an approximation of the point spread function ASF (x, y) of the imaging optical system 17 in a cylindrical shape. Here, a region inside the cylindrical shape 17e having a diameter of 2R is referred to as a point image distribution range 17l. FIG. 4C shows the relationship between the phase modulation unit region 24e on the modulation mask 24 and the point image distribution range 17l.

  As described above, the imaging surface 17f, that is, the complex amplitude distribution U (x, y) of the workpiece 18 is equal to the complex amplitude transmittance distribution T (x, y) of the modulation mask 24 and the point of the imaging optical system 17. It is given by the convolution integral with the image distribution function ASF (x, y). Here, when the point spread function ASF (x, y) is approximated by the cylindrical shape 17e as described above, the complex amplitude transmission of the modulation mask 24 in the circular point spread range 17l shown in FIG. The result of integrating the rate with a uniform weight is the complex amplitude in the image plane 17f. Then, the square of the absolute value of the complex amplitude on the image plane 17f is the intensity of the laser light irradiated on the workpiece 18.

  The integration of the complex amplitude transmittance of the modulation mask 24 in the point spread range 17l can be considered as the sum of a plurality of vectors 17h representing the complex amplitude transmittance in the unit circle 17g, as shown in FIG. 4 (d). it can. The light irradiation intensity at the corresponding position on the workpiece 18 is calculated by squaring the absolute value of the sum of the plurality of vectors 17h.

    5A and 5B show the relationship between the pupil function and the point spread function ASF (x, y) in the imaging optical system 17. FIG. In general, the point spread function ASF (x, y) shown in FIG. 5B is given by Fourier transform of the pupil function shown in FIG. When the imaging optical system 17 has a uniform circular pupil and no aberration, the point spread function ASF (x, y) is expressed by [Equation 3] as described above. However, this does not apply when there is aberration in the imaging optical system 17 or when the imaging optical system 17 has a pupil function other than the uniform circular pupil.

ここで前述の点像分布範囲１７ｌは、図４（ｂ）または図５（ｂ）に示すように、点像分布関数ＡＳＦ（ｘ，ｙ）が最初に０となるまでの円形状の中央領域、即ちエアリーディスク内側を意味することになる。なお本実施の形態において、例えばレーザ光の波長λ＝３０８ｎｍ、結像光学系１７の結像側の開口数ＮＡ＝０．１５とすると、Ｒ＝１．２５μｍとなる。 When the pupil function in the imaging optical system 17 is a uniform circular pupil and there is no aberration in the imaging optical system 17, a central region (ie, Airy) until the point spread function ASF (x, y) first becomes zero. The radius R of the disk is given by the following [Equation 5].

Here, as shown in FIG. 4B or FIG. 5B, the above-described point image distribution range 17l is a circular central region until the point image distribution function ASF (x, y) first becomes zero. That is, it means the inside of the Airy disk. In this embodiment, for example, assuming that the wavelength λ of the laser beam is 308 nm and the numerical aperture NA on the imaging side of the imaging optical system 17 is 0.15, R = 1.25 μm.

    As is apparent from FIGS. 4A to 4D, when a plurality of phase modulation unit regions 24e are included in a circle optically corresponding to the point image distribution range 17l of the imaging optical system 17, That is, when there are a plurality of vectors 17h in the unit circle 17g shown in FIG. 5D, the amplitude of light is represented by the sum of the plurality of vectors 17h. Therefore, by adjusting the complex amplitude transmittance in each phase modulation unit region 24e, the light intensity distribution can be controlled analytically and in accordance with a simple calculation.

  As is apparent from the above description, in order to freely control the intensity distribution of the light that has passed through the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b of the modulation mask 24, as shown in FIG. It is preferable that the phase modulation unit region 24e of the modulation mask transmission part 24a and the modulation mask tilt part 24b is optically smaller than the radius R of the point image distribution range 17l of the imaging optical system 17. That is, the phase modulation unit conversion region obtained by converting the phase modulation unit region 24e of the modulation mask transmission unit 24a and the modulation mask tilt unit 24b into the imaging surface 17f of the imaging optical system 17 is the point image distribution range of the imaging optical system 17. It is preferable that the radius R is smaller than at least one direction.

  Here, for example, when the magnification of the surface on the modulation mask 24 side of the imaging optical system 17 and the imaging surface 17f is 1/5, the phase modulation unit region 24e is used as the imaging surface 17f of the imaging optical system 17 described above. The modulation mask 24 is designed such that the phase modulation unit conversion region converted into is smaller in at least one direction than the radius R = 1.25 μm of the point image distribution range of the imaging optical system 17. In the present embodiment, the modulation mask 24 is designed so that the phase modulation unit area 24e of the modulation mask transmission part 24a and the modulation mask tilt part 24b is a square of 5 μm × 5 μm. In this case, the phase modulation unit conversion region obtained by converting the phase modulation unit region 24e formed of a square of 5 μm × 5 μm into the imaging surface 17f of the imaging optical system 17 is (5 μm × 5 μm) × 1/5, that is, 1 μm × 1 μm. The radius R of the point image distribution range of the imaging optical system 17 is smaller than 1.25 μm.

〔数６〕中、Ｃは定数であり、積分は点（ｘ,ｙ）を中心とする半径Ｒの内側の積分を示している。 Next, the relationship between the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b of the modulation mask 24 and the intensity I of the laser beam will be described. When the point spread function ASF (x, y) is approximated by a function having a constant value 1 inside the Airy disk and 0 outside thereof, [Equation 2] is approximated by integration inside the Airy disk ([Equation 6] ]).

In [Equation 6], C is a constant, and the integral indicates the integral inside the radius R with the point (x, y) as the center.

  Here, the operation of the phase modulation unit region 24e will be considered again. The phase modulation unit region 24e may be covered with a region having the same shape and size, or may vary from place to place. Here, when the complex amplitude transmittance does not change greatly among the plurality of phase modulation unit regions 24e within the range of the Airy disk, the integration range of [Equation 6] is expressed as (x, y) from the inside of the Airy disk. The phase modulation unit region 24e can be replaced with the inside.

ここで、Δｈは変調マスク２４に形成された凹部の深さ（凸部の高さ）を表している。 Next, a method for deriving the light intensity distribution of the light that has passed through the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b of the modulation mask 24 will be described with reference to FIGS. As described above, the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b are formed of the quartz glass 26 having a refractive index n and having an uneven surface. In this case, when the laser beam passes through the concave portion (convex portion), the wavefront is shifted by the difference between the refractive index n of the quartz glass 26 and the refractive index 1 of air, and phase modulation is performed. The phase modulation amount θ at this time is expressed by the following [Equation 7].

Here, Δh represents the depth of the concave portion formed in the modulation mask 24 (height of the convex portion).

ここで、Σは当該位相変調単位領域２４ｅにおけるすべての位相変調領域に関する和を表している。 Here, it is assumed that the depth of the concave portion (height of the convex portion) Δh is discrete, that is, processed in multiple stages, and the area ratio and the phase of the k-th phase modulation region in a certain phase modulation unit region 24e. The modulation amounts are represented as D (p) _k and θ _k , respectively. In this case, based on the above [Equation 6], the complex amplitude transmittance U and the intensity I of the laser beam on the imaging surface 17f of the imaging optical system 17 corresponding to the phase modulation unit region 24e are obtained as follows. It is done.

Here, Σ represents the sum of all phase modulation areas in the phase modulation unit area 24e.

ここでＤ（ｐ）は、各位相変調単位領域２４ｅにおける第２位相変調単位領域２５ｂの面積率を表している。この式をＤ（ｐ）に関して解くと、以下の〔数１１〕が得られる。

For the sake of simplicity, when the modulation mask 24 is composed of the modulation mask 24 shown in FIGS. 2A, 2B and 3A, 3B, that is, the modulation mask transmitting portion 24a and the modulation mask inclined portion of the modulation mask 24. Consider a case where each phase modulation unit region 24e in 24b is composed of two types of phase modulation regions (first phase modulation unit region 25a and second phase modulation unit region 25b). When the phases of the laser light modulated by the first phase modulation unit region 25a and the second phase modulation unit region 25b are expressed as θ ₁ (= 0) and θ ₂ (= θ), respectively, the intensity I of the laser light is as follows: [Expression 10]

Here, D (p) represents the area ratio of the second phase modulation unit region 25b in each phase modulation unit region 24e. When this equation is solved with respect to D (p), the following [Equation 11] is obtained.

  As described above, the intensity distribution I of the laser beam applied to the workpiece 18 based on [Equation 1] according to the size of the tapered hole 20 formed in the workpiece 18 and the inclination angle of the tapered portion 20b. Can be set. Further, the area ratio of the second phase modulation unit region 25b in each phase modulation unit region 24e can be set according to [Equation 11] so that a desired laser light intensity distribution I can be obtained. That is, by preparing the predetermined modulation mask 24, it is possible to form the tapered hole 20 having a desired size, inclination angle, and the like in the workpiece 18.

  Next, the operation of the present embodiment having such a configuration will be described.

(Modulation mask design procedure)
First, the design procedure of the modulation mask 24 will be described. First, the design procedure of the modulation mask transmission part 24a and the modulation mask inclination part 24b of the modulation mask 24 will be described with reference to FIG. FIG. 6 is a diagram showing a flowchart for designing the modulation mask transmission part 24a and the modulation mask inclination part 24b of the modulation mask 24. As shown in FIG.

(A) The modulation mask transmission part 24a and the modulation mask inclination part 24b of the modulation mask 24 are previously divided in units of the phase modulation unit region 24e. The phase modulation unit conversion region obtained by converting the phase modulation unit region 24e into the imaging surface 17f of the imaging optical system 17 is a region that is smaller in at least one direction than the radius R of the point image distribution range of the imaging optical system 17. .
(B) First, the shape of the tapered hole 20 formed in the workpiece 18 is input (S201). For example, the processing depth S (x, y) at the position (x, y) when the position on the surface on the laser beam incident side of the workpiece 18 is expressed by (x, y) coordinates is input. .
(C) Next, the laser beam irradiation frequency m is input (S202).
(D) Next, an ablation rate d (x, y) is calculated based on the processing depth S (x, y) and the number of times m of laser light irradiation (S203).
(E) Thereafter, based on the ablation rate d (x, y) and [Equation 1], the intensity distribution I (x) of the laser beam irradiated to the workpiece 18 to form the tapered hole 20 having a desired shape. , Y) is calculated (S204).
(F) Next, the area ratio D (p) of the second phase modulation unit region 25b in the modulation mask 24 is calculated based on the intensity distribution I (x, y) of the laser beam and [Equation 11] (S205). ). The area ratio D (p) is calculated for each region divided with the phase modulation unit region 24e as a unit.
(G) Finally, the pattern of the modulation mask 24 is determined based on the area ratio D (p). For example, when the phase modulation unit region 24e is a square having a side of 1 μm and the area ratio D (p) in a certain phase modulation unit region 24e is calculated to be 0.57, the side of the phase modulation unit region 24e is 0 A convex portion made of a square of .75 μm (= (0.57) ^1/2 × 1.0 μm) is formed as the second phase modulation unit region 25b.

When the tapered hole 20 shown in FIGS. 7A and 7B is formed in the workpiece 18 by irradiating the laser beam, a part of the workpiece 18 is ablated by ablation each time the pulsed laser beam is irradiated. Is removed. For this reason, after the laser beam is irradiated many times, a phenomenon occurs in which the processing surface 18 moves away from the focal plane of the imaging optical system 17 (defocusing), and thereby the laser irradiated on the processing object 18. The light intensity distribution changes. In addition, the intensity of the laser light applied to the workpiece 18 also decreases due to the influence of scattered objects generated during ablation. Therefore, when the tapered hole 20 is actually formed in the workpiece 18 by irradiating the laser beam, the inclination angle φ of the formed tapered hole 20 corresponds to the shape of the tapered hole 20 input in the above-described S201. It tends to be larger than the inclination angle φ ₁ (see FIG. 16). That is, as already described in the description of the background art, even when the intensity of the laser beam irradiated to the portion where the tapered hole 20 is formed is constant, the constant inclination angle φ ₂ is formed based on the relationship shown in FIG. The For this reason, the design of the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b of the modulation mask 24 is not performed based on the desired inclination angle φ of the tapered hole 20, but as described later in the first embodiment. This is performed based on an inclination angle φ ₁ (= φ−φ ₂ ) in consideration of a constant inclination angle φ ₂ formed based on the relationship shown in FIG.

  Next, the design procedure of the modulation mask shielding part 24c of the modulation mask 24 will be described. As shown in FIG. 2B, the modulation mask shielding part 24 c includes a quartz glass 26 and a light shielding layer 27 laminated on the quartz glass 26. In this case, the light transmittance of the modulation mask shielding part 24 c is determined by the light transmittance of the light shielding layer 27. That is, the light transmittance of the modulation mask shielding part 24 c is substantially equal to the light transmittance of the light shielding layer 27.

As described above, the light transmittance of the light shielding layer 27 of the modulation mask shielding part 24c is such that the intensity of light transmitted through the modulation mask shielding part 24c and irradiated on the non-working part 18c of the work piece 18 is determined. It is appropriately selected so as not to exceed 18 ablation thresholds. For example, when the light mask layer 27 is not provided on the modulation mask shield 24c, the light intensity on the image plane is 1000 mJ / cm ² , and the ablation threshold of the workpiece 18 is 50 mJ / cm ^2. The light shielding layer 27 is selected so that the transmittance is smaller than 0.05. For this reason, as will be described later, it is possible to prevent light having an intensity capable of processing the non-processed part 18c of the workpiece 18 from being emitted from the modulation mask shielding part 24c. It is possible to reliably prevent the 18 non-processed portions 18c from being processed.

(Taper hole forming method)
Next, a method for forming the tapered hole 20 in the workpiece 18 using the processing apparatus 10 in the present embodiment will be described.

  First, the workpiece 18 is placed on the processing table 19 in advance. Next, laser light with a uniform in-plane intensity distribution is emitted from the mask illumination system 11. Thereafter, the light emitted from the mask illumination system 11 is incident on the modulation mask 24 described above. The laser light incident on the modulation mask 24 is modulated or shielded according to the pattern of the modulation mask 24 determined by the above-described procedure.

  The laser light emitted from the modulation mask 24 is incident on the coupling optical system 17. As described above, the modulation unit conversion region obtained by converting the phase modulation unit region 24e in the modulation mask transmission unit 24a and the modulation mask tilting unit 24b of the modulation mask 24 into the imaging surface 17f of the imaging optical system 17 is the imaging optical system 17. It is designed to be smaller in at least one direction than the radius R of the point image distribution range. For this reason, the light intensity distribution of the laser light emitted from the imaging optical system 17 and imaged on the workpiece 18 after passing through the modulation mask transmission unit 24a and the modulation mask tilting unit 24b is represented by the modulation mask transmission unit 24a and the modulation mask transmission unit 24a. It has an intensity distribution corresponding to the area ratio of the first phase modulation unit region 25a and the second phase modulation unit region 25b in each phase modulation unit region 24e of the modulation mask inclined part 24b.

As described above, the occupation ratio of the first phase modulation unit region 25a in the modulation mask transmission unit 24a is Cp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Cp ₂ , so The occupation ratio of the one phase modulation unit region 25a is Tp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Tp ₂ . Here, according to the present embodiment, the modulation mask transmission part of the modulation mask 24 is satisfied so that the relationship {the absolute value of (Cp ₁ −Cp ₂ )}> {the absolute value of (Tp ₁ −Tp ₂ )} is satisfied. 24a and the modulation mask inclined part 24b are designed. Further, the distribution of Tp ₁ and Tp _{2 in} the modulation mask inclined portion 24b is from the region adjacent to the modulation mask shielding portion 24c in the modulation mask inclined portion 24b toward the region adjacent to the modulation mask transmitting portion 24a {(Tp ₁ are distributed such that the absolute value of -tp _2)} is increased. For this reason, light having high intensity is irradiated to the maximum processed portion 18a of the workpiece 18 where the through portion 20a of the tapered hole 20 is formed, and the tapered portion 20b of the tapered hole 20 of the workpiece 18 is formed. The inclined portion 18b can be irradiated with laser light having a lower intensity. Furthermore, the taper portion 20b of the tapered hole 20 can be irradiated with light whose intensity increases from the proximal end portion 20d of the tapered hole 20 toward the distal end portion 20c. This makes it possible to form the tapered hole 20 having an arbitrary inclination angle φ without reducing the light intensity. This makes it possible to reduce the variation in the inner diameter of the tip 20c of the tapered hole 20 to be formed and to shorten the time required for processing as compared with the case of the prior art that reduces the light energy.

  Note that when the workpiece 18 is processed to form the tapered hole 20, it is preferable that the workpiece 18 is entirely processed by ablation. However, the workpiece 18 is partially irradiated with laser light. It may be performed by the heat generated by.

  Further, according to the present embodiment, the modulation mask shielding part 24 c includes the light shielding layer 27 that shields light. For this reason, most of the light incident on the modulation mask shielding part 24c out of the light incident on the modulation mask 24 from the mask illumination system 11 is shielded by the light shielding layer 27 of the modulation mask shielding part 24c. Thereby, it is possible to prevent the light incident on the modulation mask 24 from the mask illumination system 11 from being transmitted through the modulation mask shielding part 24c and irradiating the non-processed part 18c of the workpiece 18, thereby It is possible to reliably prevent the non-processed portion 18c of the workpiece 18 from being processed.

(First comparison form)
Next, with reference to FIGS. 8A and 8B, the effect of the present embodiment will be described in comparison with the first comparative embodiment. FIG. 8A is a diagram showing the relationship between the energy density of light irradiated on the workpiece 18 and the workpiece 18 processed by this in the first comparative embodiment. On the other hand, FIG.8 (b) is a figure which shows the relationship between the energy density of the light irradiated to the workpiece 18, and the workpiece 18 processed by this in the 1st Embodiment of this invention. is there.

  As described above, the workpiece 18 includes the basic resin 18d and the filler 18e added to the basic resin 18d. Generally, the ablation threshold value of the filler 18e is larger than the ablation threshold value of the basic resin 18d.

  As shown in FIG. 8A, in the first comparative embodiment, the irradiation energy of light applied to the non-processed portion 18c of the workpiece 18 is larger than the ablation threshold value of the basic resin 18d, and the filler 18e. It is smaller than the ablation threshold. For this reason, as shown in FIG. 8A, the basic resin 18d is ablated in the non-processed portion 18c, whereas the filler 18e is not ablated. As a result, as shown in FIG. 8A, unevenness is formed on the surface of the non-processed portion 18c corresponding to the position where the filler 18e is added.

When the processed workpiece 18 having an uneven surface as shown in FIG. 8A is used as a nozzle of an ink jet head, the uneven portion comes into contact with the ink chamber. In this case, it is conceivable that a foreign matter existing in the ink easily adheres to the uneven portion, thereby causing a problem that the ink flow is hindered. Furthermore, it is conceivable that the ink flow easily flows in the vicinity of the concavo-convex portion, and thus the ink is likely to solidify in the vicinity of the concavo-convex portion. When the ink is solidified in the vicinity of the concavo-convex portion, this prevents the ink flow.
Thus, when the irradiation energy of the light irradiated to the non-processed part 18c of the workpiece 18 is larger than the ablation threshold of the basic resin 18d, the surface of the non-processed part 18c of the workpiece 18 is uneven. This may cause a problem that the flow of ink is hindered.

  Moreover, when the irradiation energy of the light irradiated to the non-processed part 18c of the workpiece 18 is larger than the ablation threshold value of the basic resin 18d, the following problem may further occur. One is a problem that the thickness of the workpiece 18 becomes lower than expected because the basic resin 18d of the non-processed portion 18c is ablated. In addition, a problem that debris (debris) generated by ablation processing increases may occur. Further, when a protective material or a water-repellent material is formed on the workpiece 18 before processing, these materials are ablated by the light applied to the non-processed portion 18c, and thus the surface of the workpiece 18 is protected. A problem that the function and the water repellent function are lost may also occur.

  On the other hand, according to the present embodiment, the modulation mask shielding part 24c includes the light shielding layer 27 that shields light. For this reason, most of the light incident on the modulation mask shielding part 24c out of the light incident on the modulation mask 24 from the mask illumination system 11 is shielded by the light shielding layer 27 of the modulation mask shielding part 24c. As a result, as shown in FIG. 8B, it is possible to prevent light having an irradiation energy density larger than the ablation threshold of the filler 18e and the basic resin 18d from being irradiated to the non-processed portion 18c of the workpiece 18. it can.

  For this reason, according to the present embodiment, as shown in FIG. 8B, it is possible to prevent the formation of irregularities corresponding to the position where the filler 18e is added on the surface of the non-processed portion 18c. it can. Accordingly, when the processed workpiece 18 is used as a nozzle of an ink jet head, it is possible to suppress foreign matters present in the ink from adhering to the non-processed portion 18 c of the workpiece 18. For this reason, the flow of the ink can be made smooth, and the ink can be prevented from solidifying in the non-processed portion 18 c of the workpiece 18.

  Further, according to the present embodiment, by preventing the light having an irradiation energy density larger than the ablation threshold of the filler 18e and the basic resin 18d from being irradiated to the non-processed portion 18c of the workpiece 18, the following advantages are obtained. Will be brought further. One advantage is that the thickness of the workpiece 18 can be maintained as expected by preventing the basic resin 18d of the non-processed portion 18c from being ablated. Another advantage is that debris generated by ablation can be minimized. A further advantage is that when a protective material or a water repellent material is formed on the workpiece 18 before processing, these materials can be prevented from being ablated by the light irradiated to the non-processed portion 18c. This is an advantage that the protective function and water repellent function of the surface of the workpiece 18 can be maintained.

(Second comparison form)
Next, with reference to FIG. 9 and FIGS. 10 (a) and 10 (b), the effect of the present embodiment will be described in comparison with the second comparative embodiment. FIG. 9 is a plan view showing the emission side of the modulation mask in the second comparative embodiment. FIG. 10A is an enlarged view showing a region surrounded by a thick frame in the modulation mask shown in FIG. 9, and FIG. 10B shows each amplitude modulation unit region in FIG. 10A. It is a longitudinal cross-sectional view.

  In the second comparative embodiment shown in FIG. 9 and FIGS. 10A and 10B, the modulation mask transmission part and the modulation mask inclination part each comprise a plurality of amplitude modulation unit regions. In the second comparative embodiment shown in FIGS. 9 and 10A and 10B, the same reference numerals are given to the same parts as those in the first embodiment shown in FIGS. 1 to 7 and FIG. 8B. Detailed description will be omitted.

  As shown in FIG. 9, the modulation mask 114 according to the second comparative embodiment has a modulation mask transmission part 114a for amplitude-modulating light irradiated to the through part 20a of the tapered hole 20, and a peripheral edge of the modulation mask transmission part 114a. A modulation mask inclined portion 114b for amplitude-modulating the light irradiated to the tapered portion 20b of the tapered hole 20, and a modulation corresponding to the non-processed portion 18c of the workpiece 18 positioned at the periphery of the modulation mask inclined portion 114b. It consists of a mask shielding part 114c. Of these, the modulation mask transmission part 114a and the modulation mask inclination part 114b each include a plurality of amplitude modulation unit regions 114e. On the other hand, the modulation mask shielding part 114c includes a light shielding layer 27 that shields light.

Next, the amplitude modulation unit region 114e will be described in detail. Of the modulation mask 114, for example, the modulation mask taper inclined portion 114b has amplitude modulation unit regions 114e _{1 to} 114e ₅ as shown in FIGS. Also, as shown in FIGS. 10A and 10B, the amplitude modulation unit regions 114e _{1 to} 114e ₅ of the modulation mask inclined portion 114b are respectively first amplitude modulation unit regions 115a ₁ to 115a ₁ having a first light transmittance. 15a ₅ and second amplitude modulation unit regions 115b _{1 to} 115b ₅ having a second light transmittance smaller than the first light transmittance. Here, as is apparent from FIG. 10A, in each of the amplitude modulation unit regions 114e _{1 to} 114e ₅ of the modulation mask inclined portion 114b, the occupancy rate of each of the first amplitude modulation unit regions 115a _{1 to} 115a ₅ (each amplitude modulation unit) the area ratio of the first amplitude modulation unit area 115a ₁ ~115a ₅ in the area 114e ₁ ~114e ₅₎ are different from each other. For example, the occupation ratio of the first amplitude modulation unit area 115a ₁ in the amplitude modulation unit area 114e ₁ is 0.80, and the occupation ratio of the first amplitude modulation unit area 15a ₁ in the amplitude modulation unit area 114e ₅ is 0.10. .

In the second comparative embodiment, the amplitude modulation unit conversion region obtained by converting the amplitude modulation unit regions 114 e _{1 to} 114 e ₅ to the image forming surface 17 f of the image forming optical system 17 is the radius of the point image distribution range of the image forming optical system 17. The modulation mask 114 is designed to be smaller than R in at least one direction. For this reason, as is apparent from the processing principle in the first embodiment shown in the above-mentioned formulas 1 to 6, after passing through the modulation mask inclined portion 114b, the beam is emitted from the imaging optical system 17 and on the workpiece 18. The light intensity distribution of the laser light imaged on the intensity distribution corresponding to the area ratios of the first amplitude modulation unit region 115a and the first amplitude modulation unit region 115b in each amplitude modulation unit region 114e of the modulation mask inclined portion 114b. Have. Similarly, the light intensity distribution of the laser light that is emitted from the imaging optical system 17 after passing through the modulation mask transmission part 114a and imaged on the workpiece 18 is expressed by each amplitude modulation unit region 114e of the modulation mask transmission part 114a. Has an intensity distribution corresponding to the area ratio of the first amplitude modulation unit region 115a and the first amplitude modulation unit region 115b.

As shown in FIG. 10B, each of the second amplitude modulation unit regions 115b _{1 to} 115b ₅ having the second light transmittance smaller than the first light transmittance includes the light shielding layer 27. . That is, in each of the second amplitude modulation unit regions 115b _{1 to} 115b ₅ , a second light transmittance smaller than the first light transmittance is realized by the light shielding layer 27 absorbing and reflecting light. Yes.

In the second comparative example, when the occupation ratio of the first amplitude modulation unit region 115a in the modulation mask transmission part 114a is Ca ₁ and the occupation ratio of the first amplitude modulation unit region 115a in the modulation mask tilt part 114b is Ta ₁ The modulation mask 114 is designed so that the relationship of Ca ₁ > Ta ₁ is satisfied. Further, the distribution of Ta _{1 in} the modulation mask inclined portion 114b is distributed so that Ta ₁ decreases from the region adjacent to the modulation mask transmitting portion 114a in the modulation mask inclined portion 114b toward the region adjacent to the modulation mask shielding 114c. ing. For this reason, light having high intensity is irradiated to the maximum processed portion 18a of the workpiece 18 where the through portion 20a of the tapered hole 20 is formed, and the tapered portion 20b of the tapered hole 20 of the workpiece 18 is formed. The inclined portion 18b can be irradiated with laser light having a lower intensity. Furthermore, the taper portion 20b of the tapered hole 20 can be irradiated with light whose intensity increases from the proximal end portion 20d of the tapered hole 20 toward the distal end portion 20c.

However, in the second comparative embodiment shown in FIG. 9 and FIGS. 10A and 10B, the following problems may occur. In laser processing using the modulation mask 114, the modulation mask 114 is irradiated with light having high intensity, for example, light having an intensity of 1000 mJ / cm ² . Further, as shown in FIG. 10B, in the modulation mask transmission part 114a and the modulation mask inclined part 114b of the modulation mask 114, the side end part 27a of the light shielding layer 27 is exposed to the irradiation light. Further, as described above, the light shielding layer 27 absorbs and reflects irradiated light. For this reason, in the light shielding layer 27, it is considered that heat is generated due to absorption of light. In this case, it is conceivable that the side end 27a of the light shielding layer 27 is deteriorated by heat and gradually removed each time the laser irradiation is repeated.

  Each time the laser irradiation is repeated, the side end portion 27a of the light shielding layer 27 is gradually removed. This is because the occupation ratio of the first amplitude modulation unit region 115a and the second amplitude modulation unit region 115b is increased every time the laser irradiation is repeated. It means to change. For this reason, it is conceivable that the intensity distribution of the light emitted from the modulation mask inclined portion 114b gradually changes. Thus, when the tapered hole 20 is formed in the workpiece 18 by the processing apparatus including the modulation mask 114, it is conceivable that the inclination angle of the tapered portion 20b of the tapered hole 20 gradually changes.

  On the other hand, according to the present embodiment, in the modulation mask 24, each of the modulation mask transmission part 24a and the modulation mask inclination part 24b includes a plurality of phase modulation unit regions 24e. Each phase modulation unit region 24e includes a first phase modulation unit region 25a having a first phase modulation amount and a second phase modulation unit region 25b having a second phase modulation amount. Each of the unit region 25a and the second phase modulation unit region 25b is configured by making a difference in optical distance in the quartz glass 26. For this reason, even when the laser irradiation is repeated, either the first phase modulation unit region 25a or the second phase modulation unit region 25b is not deteriorated and removed by heat. The occupation ratio of the first phase modulation unit region 25a and the second phase modulation unit region 25b does not change with time. As a result, when the tapered hole 20 is formed in the workpiece 18 by the processing apparatus 10 provided with the modulation mask 24, the tapered hole 20 having a constant inclination angle can always be formed. Further, according to the present embodiment, the modulation mask shielding part 24c includes the light shielding layer 27 made of a solid pattern. That is, there is no end portion of the light shielding layer 27 exposed to the irradiation light inside the modulation mask shielding portion 24c. For this reason, the light shielding layer 27 is not deteriorated and removed by heat inside the modulation mask shielding part 24 c, so that light having an irradiation energy density larger than the ablation threshold value is applied to the workpiece 18. Irradiation to the non-processed part 18c can always be reliably prevented.

In the present embodiment, an example is shown in which the energy density I of the laser beam is set so as not to exceed I _upper . However, the present invention is not limited to this, and the energy density I of the laser beam may be set to a value exceeding I _upper . In this case, the energy density I of the laser beam is set in consideration of the absorption and scattering of the laser beam caused by the scattered matter generated when a part of the workpiece 18 is removed.

  In the present embodiment, the laser light source 12 is an XeCl excimer laser light source 12 that supplies light having a wavelength of 308 nm. However, the present invention is not limited to this, and the laser light source 12 that supplies light having a wavelength other than 308 nm may be used as the laser light source 12. In this case, the wavelength of the laser light source 12 takes into consideration the material of the workpiece 18, the magnification between the surface of the imaging optical system 17 on the modulation mask 24 side and the imaging surface, the aperture ratio NA of the imaging optical system 17, and the like. To be determined.

  Moreover, in this Embodiment, the example in which the filler 18e was added to the basic resin 18d of the workpiece 18 was shown. However, the present invention is not limited to this, and the workpiece 18 may not have the filler 18e.

  Moreover, in this Embodiment, the example in which the taper hole 20 which has the penetration part 20a and the taper part 20b in the to-be-processed object 18 by the processing apparatus 10 was formed was shown. However, the present invention is not limited to this, and the machining apparatus 10 may form a non-through tapered hole 20 in the workpiece 18, that is, a tapered hole 20 having a bottom portion and a tapered portion 20b. Alternatively, as shown in FIG. 11, a cylindrical straight portion 20e extending in parallel with the laser beam irradiation direction from the distal end portion 20c and a taper from the proximal end portion 20d toward the straight portion 20e and a smooth straight portion e. A tapered hole 20 having a tapered portion 20b connected to the tapered portion 20b may be formed.

  Further, in the present embodiment, the example in which the modulation mask 24 is designed so that the phase modulation unit region 24e of the modulation mask transmission part 24a and the modulation mask tilt part 24b is a square of 5 μm × 5 μm is shown. However, the present invention is not limited to this, and the phase modulation unit conversion region obtained by converting the phase modulation unit region 24e into the imaging surface 17f of the imaging optical system 17 is based on the radius R of the point image distribution range of the imaging optical system 17. As long as the modulation mask 24 becomes smaller in at least one direction, the modulation mask 24 can be arbitrarily designed.

  Further, in the present embodiment, the modulation mask 24 is set so that the first phase modulation amount in the first phase modulation unit region 25a and the second phase modulation amount in the second phase modulation unit region 25b differ by an odd multiple of 180 degrees. An example where is designed. However, the present invention is not limited to this, and as shown in [Equation 11], it is possible to arbitrarily set the phase modulation amount difference.

  In the present embodiment, each phase modulation unit region 24e of the modulation mask transmitting unit 24a and the modulation mask tilting unit 24b is divided into two types of phase modulation regions (first phase modulation unit region 25a and second phase modulation unit region 25b). An example is shown. However, the present invention is not limited to this, and each phase modulation unit region 24e may be formed of three or more types of phase modulation regions.

  In the present embodiment, the modulation mask transmission unit 24a of the modulation mask 24 is composed of a plurality of phase modulation unit regions 24e, and the light that is phase-modulated by the modulation mask transmission unit 24a and emitted is connected to the imaging optical system 17. An example is shown in which a light intensity distribution based on the phase modulation unit region 24e is generated on the image surface 17f. However, the present invention is not limited to this, and the modulation mask transmission unit 24a may be formed so that light incident on the modulation mask transmission unit 24a is emitted from the modulation mask transmission unit 24a without being phase-modulated. For example, the quartz glass 26 constituting the modulation mask transmission part 24a may have a single height throughout the modulation mask transmission part 24a. In this case, the light incident on the modulation mask transmission part 24a is emitted from the modulation mask transmission part 24a with substantially the same intensity as the incident light. For this reason, it is possible to irradiate the maximum processing portion 18a of the workpiece 18 with light having higher intensity, thereby reducing variations in the inner diameter of the tip portion 20c of the tapered hole 20 to be formed and processing. Can be shortened. Moreover, since the quartz glass 26 constituting the modulation mask transmission part 24a has a single height, the modulation mask transmission part 24a of the modulation mask 24 can be manufactured more easily.

  Moreover, in this Embodiment, the example in which the taper hole 20 which has circular shape was formed in the to-be-processed object 18 was shown. However, the present invention is not limited to this, and a tapered hole 20 having an elliptical shape, a rectangular shape, or other various shapes may be formed in the workpiece 18.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment shown in FIGS. 12 and 13, by irradiating the workpiece including the non-processed portion with the light emitted from the light source, the workpiece is provided with at least one inclined portion, A maximum processing portion located on the bottom side of the inclined portion is formed. The modulation mask includes a modulation mask inclined portion that phase-modulates light applied to the inclined portion of the workpiece, and a modulation mask that is adjacent to one side of each modulation mask inclined portion and corresponds to a non-worked portion of the workpiece. It has a shielding part and a modulation mask transmission part adjacent to the other side of each modulation mask inclined part and corresponding to the maximum processed part of the workpiece. In the second embodiment shown in FIG. 12 and FIG. 13, the same parts as those in the first embodiment shown in FIG. 1 to FIG. 7 and FIG. To do.

(Workpiece)
First, the inclined portion 18b formed on the workpiece 18 will be described with reference to FIGS. Fig.13 (a) is a top view which shows the to-be-processed object 18 in this Embodiment, FIG.13 (b) is the longitudinal cross-section which looked at the to-be-processed object 18 of Fig.13 (a) from the XIIIb-XIIIb direction. FIG.

  As shown in FIGS. 13A and 13B, the inclined portion 18 b formed on the workpiece 18 is a portion inclined downward from the non-processed portion 18 c that is the uppermost surface of the workpiece 18. Yes. Further, as shown in FIGS. 13A and 13B, a maximum processing portion 18a is formed on the bottom side (lower side) of the inclined portion 18b. The maximum processed portion 18 a is a portion of the workpiece 18 that is processed most deeply by the processing device 10, and the non-processed portion 18 c is processed by the processing device 10 of the workpiece 18. This is an undesirable part.

(Modulation mask)
Next, the modulation mask 31 in the present embodiment will be described with reference to FIGS. 12A is a plan view showing the modulation mask 31 when viewed from the emission side of the modulation mask 31, and FIG. 12B shows the modulation mask 31 of FIG. 12A from the XIIb-XIIb direction. FIG.

  As shown in FIG. 12A, the modulation mask 31 is adjacent to the modulation mask inclined portion 24b that phase-modulates the light applied to the inclined portion 18b of the workpiece 18, and one side 24f of the modulation mask inclined portion 24b. The phase of the light irradiated to the maximum processing portion 18a of the workpiece 18 adjacent to the modulation mask shielding portion 24c corresponding to the non-processing portion 18c of the workpiece 18 and the other side 24g of the modulation mask inclined portion 24b. And a modulation mask transmission part 24a for modulation. Similarly to the case of the first embodiment shown in FIGS. 1 to 7 and FIG. 8B, each of the modulation mask transmission part 24a and the modulation mask inclination part 24b is composed of a plurality of phase modulation unit regions 24e ( (Refer FIG. 12 (a) (b)). On the other hand, as shown in FIG. 12B, the modulation mask shielding portion 24c includes a light shielding layer 27 that shields light. The modulation mask 31 is provided with a number of modulation mask inclined portions 24b corresponding to the number of inclined portions 18b formed on the workpiece 18. In the present embodiment, the modulation mask 31 is provided with the modulation mask inclined portions. The case where one part 24b is provided will be described.

  As in the case of the first embodiment shown in FIGS. 1 to 7 and FIG. 8B, the light that is phase-modulated and emitted by the modulation mask transmitting section 24a and the modulation mask tilt section 24b of the modulation mask 31 is A light intensity distribution based on each phase modulation unit region 24e is generated on the imaging surface (workpiece 18) of the imaging optical system 17. Each phase modulation unit region 24e includes a first phase modulation unit region 25a having a first phase modulation amount and a second phase modulation unit region 25b having a second phase modulation amount. Since the phase modulation unit region 24e in the present embodiment is the same as the phase modulation unit region 24e in the first embodiment shown in FIGS. 1 to 7 and FIG. 8B, detailed description thereof is omitted.

Next, the occupation ratio of the first phase modulation unit region 25a and the occupation ratio of the second phase modulation unit region 25b in the modulation mask transmission unit 24a and the modulation mask inclination unit 24b will be described. In the present embodiment, the occupation ratio of the first phase modulation unit region 25a in the modulation mask transmission section 24a is Cp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Cp ₂ . Similarly, the occupation ratio of the first phase modulation unit region 25a in the modulation mask inclined portion 24b is Tp ₁ , and the occupation ratio of the second phase modulation unit region 25b is Tp ₂ . At this time, the modulation mask 31 is designed so that the relationship {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied. Further, the distribution of Tp ₁ and Tp _{2 in} the modulation mask inclined portion 24b is from the region adjacent to the modulation mask shielding portion 24c in the modulation mask inclined portion 24b toward the region adjacent to the modulation mask transmitting portion 24a {(Tp ₁ are distributed such that the absolute value of -tp _2)} is increased.

  Next, the modulation mask shielding part 24c will be described in detail. As described above, the modulation mask shielding part 24c includes the light shielding layer 27 that shields light. For this reason, most of the light incident on the modulation mask shielding part 24c out of the light incident on the modulation mask 31 from the mask illumination system 11 is shielded by the light shielding layer 27 of the modulation mask shielding part 24c. As a result, it is possible to prevent light incident on the modulation mask 31 from the mask illumination system 11 from being transmitted through the modulation mask shielding part 24c and being irradiated to the non-processed part 18c of the workpiece 18. It is possible to reliably prevent the non-processed portion 18c of the workpiece 18 from being processed.

  As described above, according to the present embodiment, the modulation mask 31 is provided on the modulation mask inclined portion 24b for phase-modulating the light applied to the inclined portion 18b of the workpiece 18, and on one side 24f of the modulation mask inclined portion 24b. Light that is adjacent to the modulation mask shielding part 24c corresponding to the non-processed part 18c of the workpiece 18 and the other side 24g of the modulation mask inclined part 24b and that is irradiated on the maximum processing part 18a of the workpiece 18 is irradiated. A modulation mask transmission part 24a for phase modulation. Among these, the modulation mask shielding part 24 c includes a light shielding layer 27 that shields light. For this reason, it can prevent that the light which has the intensity | strength which can process the workpiece 18 is irradiated to the non-processed part 18c of the workpiece 18, and, thereby, the non-processed part 18c is processed. Can be surely prevented.

Further, according to the present embodiment, the modulation mask tilt part 24 b is composed of a plurality of phase modulation unit areas 24 e, and the light that is phase-modulated by the modulation mask tilt part 24 b and emitted is connected to the imaging optical system 17. A light intensity distribution based on the phase modulation unit region 24e is generated on the image plane 17f. In addition, the phase modulation unit conversion region obtained by converting the phase modulation unit region 24e to the imaging surface 17f of the imaging optical system 17 is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system 17. The phase modulation unit region 24e includes a first phase modulation unit region 25a having a first phase modulation amount and a second phase modulation unit region 25b having a second phase modulation amount. Therefore, the distribution of Tp ₁ and Tp ₂ in the modulation mask inclined part 24b is changed from the area adjacent to the modulation mask shielding part 24c to the area adjacent to the modulation mask transmitting part 24a in the modulation mask inclined part 24b {(Tp ₁₋ Tp ₂ )} is increased so that the intensity of light applied to the inclined portion 18b of the workpiece 18 is changed from the non-machined portion 18c of the workpiece 18 to the maximum machined portion 18a. It can be adjusted so as to increase continuously. Thereby, the inclined portion 18b having a desired inclination angle can be formed on the workpiece 18 with high accuracy in a short processing time.

Modified Example Next, a modified example of the second embodiment of the present invention will be described with reference to FIGS. 14 and 15 differ only in that the maximum processed portion is not formed on the workpiece including the non-processed portion, and the other configuration is the second configuration shown in FIGS. 12 and 13. This is substantially the same as the embodiment. In the modification of the second embodiment shown in FIGS. 14 and 15, the same parts as those of the second embodiment shown in FIGS. 12 and 13 are denoted by the same reference numerals, and detailed description thereof is omitted.

(Workpiece)
With reference to FIG. 15 (a) (b), the to-be-processed object 18 in this modification is demonstrated. FIG. 15A is a plan view showing the workpiece 18 in this modification, and FIG. 15B is a longitudinal sectional view of the workpiece of FIG. 15A viewed from the XVb-XVb direction. is there.

  As shown in FIGS. 15 (a) and 15 (b), in this modification, an inclined portion 18b is formed on the workpiece 18 including the non-processed portion 18c by the processing by the processing apparatus 10.

(Modulation mask)
Next, with reference to FIGS. 14A and 14B, the modulation mask 33 in the present embodiment will be described. 14A is a plan view showing the modulation mask 33 when viewed from the emission side of the modulation mask 33, and FIG. 14B shows the modulation mask 33 of FIG. 14A from the XIVb-XIVb direction. FIG.

  As shown in FIG. 14A, the modulation mask 33 is adjacent to the modulation mask inclined portion 24b that modulates the phase of the light irradiated to the inclined portion 18b of the workpiece 18, and the modulation mask inclined portion 24b. And a modulation mask shielding part 24c corresponding to the non-processed part 18c of the object 18. Similarly to the case of the second embodiment shown in FIGS. 12 and 13, the modulation mask inclined portion 24b is composed of a plurality of phase modulation unit regions 24e (see FIGS. 14A and 14B). On the other hand, as shown in FIG. 14B, the modulation mask shielding part 24c includes a light shielding layer 27 that shields light. Since the phase modulation unit region 24e in this modification is the same as the phase modulation unit region 24e in the first embodiment shown in FIGS. 1 to 7 and FIG. 8B, detailed description thereof is omitted.

In this modification, when the occupation ratio of the first phase modulation unit region 25a in the modulation mask inclined portion 24b is Tp ₁ and the occupation ratio of the second phase modulation unit region 25b is Tp ₂ , Tp ₁ in the modulation mask inclined portion 24b. The distribution of Tp ₂ is such that {the absolute value of (Tp ₁ −Tp ₂ )} increases as the distance from the region adjacent to the modulation mask shielding unit 24 c in the modulation mask inclined unit 24 b increases. For this reason, the intensity of light applied to the inclined portion 18b of the workpiece 18 can be adjusted so as to continuously increase as the distance from the non-processing portion 18c of the workpiece 18 increases. Thereby, the inclined portion 18b having a desired inclination angle can be formed on the workpiece 18 with high accuracy in a short processing time.

  Further, according to the present modification, the modulation mask shielding part 24 c includes the light shielding layer 27 that shields light. For this reason, it can prevent that the light which has the intensity | strength which can process the workpiece 18 is irradiated to the non-processed part 18c of the workpiece 18, and, thereby, the non-processed part 18c is processed. Can be surely prevented.

Example 1
Next, examples of the present invention will be described. First, an example (Example 1) in which the tapered hole 20 is formed in the workpiece 18 using the processing apparatus 10 including the modulation mask 24 according to the first embodiment of the present invention will be described with reference to FIGS. The description will be given with reference.

  16A is a longitudinal sectional view showing the shape of the tapered hole 20 formed in the workpiece 18 in the first embodiment, and FIG. 16B is a tapered hole 20 shown in FIG. FIG. 16C shows the tapered hole 20 formed in the workpiece 18 in the first embodiment. FIG. 16C shows the intensity distribution I of the laser beam irradiated on the workpiece 18 to form the workpiece. It is a top view. FIG. 17A is a plan view showing the modulation mask 24 in the first embodiment, and FIG. 17B is a diagram showing the intensity of light emitted from the modulation mask 24 shown in FIG. . FIG. 18A is a diagram showing the shape of the second phase modulation unit region of the phase modulation unit region, and FIG. 18B shows the dimensional error of the second phase modulation unit region and the second phase modulation unit. It is a figure which shows the relationship with the intensity | strength of the light modulated by the phase modulation unit area | region containing an area | region.

Using the modulation mask 24 of the present invention, a tapered hole 20 having a diameter of the base end portion 20d of 50 μm and an inclination angle φ of the taper portion 20b of 12 degrees was formed on the workpiece 18 (FIG. 16A). . The workpiece 18 includes a basic resin 18d made of a polyimide film having a thickness of 50 μm, an absorption coefficient α of 1.43 μm ⁻¹ , and an ablation threshold I _th of 50 mJ / cm ² , and an ablation threshold I _th of 200 mJ / cm. A workpiece 18 having ² filler 18e was used.

The details of the optical characteristics of the processing apparatus 10 used in Example 1 are as follows.
(1) a light source a laser light source: XeCl excimer laser, wavelength: 308 nm, light intensity: (40 mJ / ^cm 2 on the modulation mask surface) on the image plane 1000 mJ / cm ²
(2) Phase modulation amount Difference between phase modulation amount of first phase modulation unit region and modulation amount of second phase modulation unit region: 180 degrees (3) Imaging optical system Imaging optical system magnification: 1/5, imaging Side numerical aperture (NA): 0.15
(4) Coherent factor 0.5
In this case, the radius R of the point image distribution range of the imaging optical system 17 is 1.25 μm. Accordingly, the phase modulation unit conversion region obtained by converting the phase modulation unit region 24e of the modulation mask transmission unit 24a and the modulation mask tilting unit 24b of the modulation mask 24 into the imaging surface 17f of the imaging optical system 17 The phase modulation unit region 24e of the modulation mask transmission part 24a and the modulation mask inclination part 24b is set to be a square having a side of 5 μm (the imaging surface 17f of the imaging optical system 17) so that it is smaller than the radius R of the point image distribution range. The phase modulation unit conversion region converted into is set to a square having a side of 1 μm.

First, based on the flowchart shown in FIG. 6, the modulation mask transmission part 24a and the modulation mask inclination part 24b of the modulation mask 24 used in Example 1 were designed. First, the shape of the tapered hole 20 formed in the workpiece 18 was input (S201). Note that the tilt angle φ ₁ (= φ−φ ₂ ) input in S201 is set to 6 degrees because 6 degrees is estimated as the tilt angle φ ₂ generated due to the influence of scattered objects generated during ablation. Next, the number m of times of laser beam irradiation was input (S202). In Example 1, the number m of laser light irradiation was 150. Thereby, the ablation rate d is calculated (S203). Based on this ablation rate d and [Equation 1], the intensity distribution I of the laser beam applied to the workpiece 18 in order to form the tapered hole 20 having a desired shape was calculated.

  Next, based on the calculated intensity distribution I of the laser light and [Equation 11], the area ratio D of the second phase modulation unit region 25b in each phase modulation unit region 24e of the modulation mask transmission unit 24a and the modulation mask inclination unit 24b. (P) was calculated (S205). The area ratio D (p) was calculated for each region divided with the phase modulation unit region 24e as a unit. Thereafter, based on the calculated area ratio D (p), the patterns of the modulation mask transmission part 24a and the modulation mask inclination part 24b were determined (S206). Next, a modulation mask 24 having the determined pattern was produced. The upper right part of the obtained modulation mask 24 is shown in FIG. In Example 1, the light shielding layer 27 (light shielding layer having a light transmittance of 0) provided in the modulation mask shielding part 24c was selected so that the light transmittance in the modulation mask shielding part 24c was zero.

Here, the relationship between the intensity of light emitted from the modulation mask 24 and the manufacturing error of the modulation mask 24 will be described. FIG. 18A is a plan view and a cross section of a phase modulation unit region 24e having a first phase modulation unit region 25a with an occupation ratio of 0.5 and a second phase modulation unit region 25b with an occupation ratio of 0.5. The figure is shown. Here, s ₁ is has a dimension of one side of the second phase modulation unit regions 25b, s ₂ is a height difference between the first phase modulation unit region 25a and the second phase modulation unit region 25b ing.

FIG. 18B shows the phase modulation unit region 24e shown in FIG. 18A when the dimensions s ₁ and s ₂ shown in FIG. It is a graph which shows how much the normalized intensity | strength on the imaging surface of the modulated light shift | deviates from 0 which is a design value. In the normalization, the intensity on the imaging surface of the light modulated by the modulation mask in which the occupation ratio of the first phase modulation unit area = 1 (or the occupation ratio of the second phase modulation unit area = 1) is 1 It is said.
In the graph shown in FIG. 18B, the horizontal axis represents the difference between the phase modulation amount of the first phase modulation unit region 25a and the phase modulation amount of the second phase modulation unit region 25b when 180 degrees is the reference. The manufacturing error is shown. For example, an error of 5% of the difference in the phase modulation amount θ means that the difference in the phase modulation amount θ is shifted from the design value of 180 degrees by 9 degrees. As is apparent from the description of the first embodiment described above, production error of the difference in phase modulation amount corresponds to the manufacturing error of the dimension s _2.
In the graph shown in FIG. 18 (b), the vertical axis indicates the production error of the dimensions s ₁ of the second phase modulation unit region 25b (deviation from the design value).
In the graph shown in FIG. 18B, the dotted line 35a indicates that the normalized intensity of the light modulated by the phase modulation unit region 24e is 0.025 when the production error is a value on the dotted line 35a. Is meant to be. For example A point on the dotted line 35a is produced an error of 10% of the difference in phase modulation amount, when manufacturing error of the dimension s ₁ is 0% normalized intensity on the focal plane 0.025 Is meant to be. Similarly, in the case of the alternate long and short dash line 35b, when the manufacturing error is a value on the alternate long and short dash line 31b, the normalized intensity of the light modulated by the phase modulation unit region 24e is 0.05 from the design value. Means. The two-dot chain line 35c means that the normalized intensity of the light modulated by the phase modulation unit region 24e is 0.075 when the production error is a value on the two-dot chain line 35c. doing.

  Next, the intensity of light emitted from the modulation mask 24 created in the present embodiment will be described. FIG. 17B is a graph showing the intensity of light emitted from the modulation mask 24 of the present embodiment shown in FIG. Of these, the line 32a is a line indicating the design value of the intensity of light emitted from the modulation mask 24 of the present embodiment, and the line 32b represents the intensity of light actually emitted from the modulation mask 24 of the present embodiment. It is a line to show.

In the present embodiment, the modulation mask transmitting portion 24a of the modulation mask 24 and the phase modulation unit regions 24e of the modulation mask tilting portion 24b are patterned on a resist (not shown) by exposure with a laser, an electron beam or the like, and then RIE. It is manufactured by dry etching such as (ReactIve Ion EtchIng). This processing depth is controlled by the etching time. However, some variation is unavoidable in the etching rate (the amount etched in a certain time), and as a result, the phase modulation of the first phase modulation unit region 25a and the second phase modulation unit region 25b of each phase modulation unit region 24e. A production error occurs in the quantity θ.
Further, the side dimension of the second phase modulation unit region 25b is controlled by the exposure condition, the development condition, and the etching condition. However, some variation is unavoidable in these conditions, and as a result, a manufacturing error occurs in one side dimension of the second phase modulation unit region 25b. Even if there is no production error in the basic dimensions, the corners of the pattern such as a square are rounded due to the resolution limit of these processes. For these reasons, the occupation ratios of the first phase modulation unit region 25a and the second phase modulation unit region 25b deviate from the design values.
For this reason, as shown in FIG. 17B, in this embodiment, a line 32b indicating the intensity of light actually emitted from the modulation mask transmitting portion 24a and the modulation mask inclined portion 24b of the modulation mask 24 is a design value. Deviation from 32a.

  On the other hand, in this embodiment, the modulation mask shielding part 24 c includes the light shielding layer 27. As shown in FIG. 17A, the light shielding layer 27 has a solid pattern, and therefore the light transmittance in the modulation mask shielding portion 24c is hardly affected by the manufacturing error. For this reason, the light transmittance in the modulation mask shielding part 24c can be surely made zero over the entire area of the modulation mask shielding part 24c. As a result, as shown in FIG. 17B, the intensity of light actually emitted from the modulation mask shielding part 24c can be made zero. Thereby, it was possible to reliably prevent the non-processed portion 18c of the workpiece 18 from being processed.

(Comparative Example 1)
Next, an example in which the tapered hole 20 is formed in the workpiece 18 using the processing apparatus 10 including the modulation mask 124 shown in FIG. 19A will be described with reference to FIGS. 19A and 19B. To do. Here, FIG. 19A is a plan view showing the modulation mask 124 in Comparative Example 1, and FIG. 19B is a view showing the intensity of light emitted from the modulation mask 124 shown in FIG. It is.

  The modulation mask 124 shown in FIG. 19A is different from the modulation mask 124 only in that the modulation mask shielding part 124c of the modulation mask 124 includes a plurality of phase modulation unit regions 24e. 24. In the modulation mask 124 shown in FIG. 19A, the same parts as those of the modulation mask 24 in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 19A, the modulation mask shielding part 124c of the modulation mask 124 includes a plurality of phase modulation unit regions 24e. Each phase modulation unit region 24e of the modulation mask shielding part 124c includes a first phase modulation unit region 25a having a first phase modulation amount and a second phase modulation unit region 25b having a second phase modulation amount. It has become. The difference between the phase modulation amount of the first phase modulation unit region 25a and the phase modulation amount of the second phase modulation unit region 25b is 180 degrees. In the modulation mask shielding part 124c, the occupation ratio of the first phase modulation unit area 25a in each phase modulation unit area 24e is 0.5, and the occupation ratio of the second phase modulation unit area 25b is also 0.5. It has become.

  Next, the intensity of light emitted from the modulation mask 124 created in this comparative example will be described. FIG. 19B is a graph showing the intensity of light emitted from the modulation mask 124 of this comparative example shown in FIG. Of these, the line 132a is a line indicating the design value of the intensity of light emitted from the modulation mask 124 of this comparative example, and the line 132b represents the intensity of light actually emitted from the modulation mask 124 of this comparative example. It is a line to show.

  As described above, in the modulation mask shielding part 124c, the occupation ratio of the first phase modulation unit area 25a in each phase modulation unit area 24e is 0.5, and the occupation ratio of the second phase modulation unit area 25b is also 0. .5. For this reason, as shown in FIG. 19B, the design value of the intensity of the light emitted from the modulation mask shielding part 124c of the modulation mask 124 is zero (see the line 132a).

However, as in the case of the first embodiment, each phase modulation unit region 24e of the modulation mask shielding part 124c of the modulation mask 124 is patterned by, for example, exposure to a resist (not shown) with a laser or an electron beam, and then RIE. It is manufactured by dry etching such as (ReactIve Ion EtchIng). This processing depth is controlled by the etching time. However, some variation is unavoidable in the etching rate (the amount etched in a certain time), and as a result, the phase modulation of the first phase modulation unit region 25a and the second phase modulation unit region 25b of each phase modulation unit region 24e. A production error occurs in the quantity θ.
Further, the side dimension of the second phase modulation unit region 25b is controlled by the exposure condition, the development condition, and the etching condition. However, some variation is unavoidable in these conditions, and as a result, a manufacturing error occurs in one side dimension of the second phase modulation unit region 25b. Even if there is no production error in the basic dimensions, the corners of the pattern such as a square are rounded due to the resolution limit of these processes. For these reasons, the occupation ratios of the first phase modulation unit region 25a and the second phase modulation unit region 25b deviate from the design values.

  Therefore, in the modulation mask shielding part 124c, the occupation ratio of the first phase modulation unit area 25a in each phase modulation unit area 24e is shifted from 0.5 to one, and the occupation ratio of the second phase modulation unit area 25b is also 0. .5 shifted to the other. For this reason, as shown in FIG. 19B, the intensity of the light actually emitted from the modulation mask shielding part 124c of the modulation mask 124 is not zero, and is larger than the ablation threshold of the basic resin 18d, And it was intensity | strength smaller than the ablation threshold value of the filler 18e. Therefore, when forming the tapered hole 20 in the workpiece 18 using the processing apparatus 10 including the modulation mask 124, the basic resin 18d is ablated in the non-processed portion 18c, whereas the filler 18e is ablated. Not. For this reason, the unevenness | corrugation was formed in the surface of the non-processed part 18c corresponding to the position where the filler 18e was added.

DESCRIPTION OF SYMBOLS 10 Processing apparatus 11 Mask illumination system 12 Laser light source 13 Illumination optical system 17 Imaging optical system 17a Convex lens 17b Convex lens 17c Aperture stop 17e Cylindrical 17f Imaging surface 17g Unit circle 17h Vector 17k Opening part 17l Point image distribution range 18 Workpiece 18a Maximum processed portion 18b Inclined portion 18c Non-processed portion 18d Basic resin 18e Filler 19 Processing base 20 Tapered hole 20a Tapered hole penetrating portion 20b Tapered hole tapered portion 20c Tapered hole distal end portion 20d Tapered hole proximal end portion 20e Tapered hole Straight portion 24 of modulation mask 24a Modulation mask transmission portion 24b Modulation mask tilt portion 24c Modulation mask shielding portion 24e Phase modulation unit region 24f One side 24g of modulation mask tilt portion Other side 25a of modulation mask tilt portion First phase modulation unit region 25b Second phase modulation unit region 26 quartz glass 27 Light shielding layer 27a Side end 31 Modulation mask 32a Line indicating light intensity (design value)
32b Line indicating light intensity (actual measurement)
33 Modulating mask 100 Conventional processing apparatus 101 Light source 102 Laser light source 103 Illumination optical system 104 Mask 105 Silica glass layer 106 Light shielding layer 106a Opening 107 Imaging optical system 108 Nozzle forming sheet 109 Stage 110 Nozzle 110b Nozzle taper 110c Nozzle tip portion 114 Modulation mask 114a Modulation mask transmission portion 114b Modulation mask inclination portion 114c Modulation mask shielding portion 114e Amplitude modulation unit region 115a First amplitude modulation unit region 115b Second amplitude modulation unit region 124 Modulation mask 124c Modulation mask shielding portion 132a Light intensity line (design value)
132b Light intensity line (actual measurement)

Claims (14)

In the processing apparatus for forming at least one inclined portion on the workpiece by irradiating the workpiece including the non-processing portion with the light emitted from the light source,
A light source that emits light;
A modulation mask that is provided on the emission side of the light source and modulates and emits light from the light source;
An imaging optical system that is provided on the emission side of the modulation mask, forms an image of light modulated by the modulation mask and irradiates the workpiece, and forms an inclined portion on the workpiece;
The modulation mask includes a modulation mask inclined portion for phase-modulating light applied to the inclined portion of the workpiece, and a modulation mask shield that is adjacent to each modulation mask inclined portion and corresponds to a non-processed portion of the workpiece. And
The modulation mask tilt part is composed of a plurality of phase modulation unit areas, and light emitted after being phase-modulated by the modulation mask tilt part is distributed on the imaging plane of the imaging optical system based on the phase modulation unit areas. Produces
The modulation mask shielding part includes a light shielding layer that shields light,
The phase modulation unit conversion region obtained by converting the phase modulation unit region into the imaging surface of the imaging optical system is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system,
The radius R of the point image distribution range of the imaging optical system is defined as R = 0.61λ / NA, where λ is the center wavelength of light and NA is the numerical aperture on the exit side of the imaging optical system,
The phase modulation unit region includes a first phase modulation unit region having a first phase modulation amount and a second phase modulation unit region having a second phase modulation amount,
Tp 1 occupancy of the first phase modulation unit area in the modulation mask inclined _portion, when the occupation rate of the second phase modulation unit areas and Tp _2, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, modulation The processing apparatus is characterized in that {absolute value of (Tp ₁ −Tp ₂ )} is distributed so as to increase as the distance from the region adjacent to the modulation mask shielding portion in the mask inclined portion increases. In the workpiece, at least one inclined portion and a maximum processed portion located on the bottom side of the inclined portion are formed by processing by a processing device,
The modulation mask includes a modulation mask inclination portion that phase-modulates light irradiated to the inclination portion, a modulation mask shielding portion that is adjacent to one side of each modulation mask inclination portion, and that corresponds to the non-processed portion, and each modulation The processing apparatus according to claim 1, further comprising: a modulation mask transmission portion adjacent to the other side of the mask inclined portion and corresponding to the maximum processing portion. The modulation mask transmission unit includes a plurality of phase modulation unit regions, and light intensity distribution based on the phase modulation unit regions is generated on the imaging plane of the imaging optical system by the light phase-modulated by the modulation mask transmission unit. Which generates
The occupation ratio of the first phase modulation unit area in the modulation mask transmitting section is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation ratio of the first phase modulation unit area in the modulation mask tilt section is Tp. ₁ , when the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied The processing apparatus according to claim 2. In a processing apparatus for forming at least one tapered tapered hole having a penetrating portion or a bottom portion and a tapered portion on a workpiece by irradiating the workpiece with light emitted from a light source,
A light source that emits light;
A modulation mask that is provided on the emission side of the light source and modulates and emits light from the light source;
An imaging optical system that is provided on the emission side of the modulation mask, forms an image of light modulated by the modulation mask and irradiates the workpiece, and forms a tapered hole in the workpiece;
The modulation mask is positioned at the periphery of each modulation mask transmission portion corresponding to the light irradiated to the through portion or bottom portion of the taper hole, and the light irradiated to the taper portion of the taper hole. A modulation mask inclined part for phase modulation, and a modulation mask shielding part located at the periphery of each modulation mask inclined part,
The modulation mask tilt part is composed of a plurality of phase modulation unit areas, and light emitted after being phase-modulated by the modulation mask tilt part is distributed on the imaging plane of the imaging optical system based on the phase modulation unit areas. Produces
The modulation mask shielding part includes a light shielding layer that shields light,
The phase modulation unit conversion region obtained by converting the phase modulation unit region into the imaging surface of the imaging optical system is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system,
The radius R of the point image distribution range of the imaging optical system is defined as R = 0.61λ / NA, where λ is the center wavelength of light and NA is the numerical aperture on the exit side of the imaging optical system,
The phase modulation unit region includes a first phase modulation unit region having a first phase modulation amount and a second phase modulation unit region having a second phase modulation amount,
Tp 1 occupancy of the first phase modulation unit area in the modulation mask inclined _portion, when the occupation rate of the second phase modulation unit areas and Tp _2, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, modulation The distribution is such that {the absolute value of (Tp ₁ −Tp ₂ )} increases from a region adjacent to the modulation mask shielding portion to a region adjacent to the modulation mask transmission portion in the mask inclined portion. Processing equipment. The modulation mask transmission unit includes a plurality of phase modulation unit regions, and light intensity distribution based on the phase modulation unit regions is generated on the imaging plane of the imaging optical system by the light phase-modulated by the modulation mask transmission unit. Which generates
The occupation ratio of the first phase modulation unit area in the modulation mask transmitting section is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation ratio of the first phase modulation unit area in the modulation mask tilt section is Tp. ₁ , when the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied The processing apparatus according to claim 4.   The processing apparatus according to claim 1, wherein the workpiece includes a basic resin and a filler added to the basic resin.   7. The first phase modulation amount of the first phase modulation unit region and the second phase modulation amount of the second phase modulation unit region differ by an odd multiple of 180 degrees. The processing apparatus in any one. In a modulation mask incorporated in a processing apparatus that forms at least one inclined portion in a workpiece by irradiating the workpiece including the non-processing portion with light emitted from the light source,
The processing equipment
A light source that emits light;
A modulation mask that is provided on an emission side of the light source and that modulates and emits light from the light source; and
An imaging optical system that is provided on the emission side of the modulation mask, forms an image of light modulated by the modulation mask and irradiates the workpiece, and forms an inclined portion on the workpiece;
The modulation mask includes a modulation mask inclined portion for phase-modulating light applied to the inclined portion of the workpiece, and a modulation mask shield that is adjacent to each modulation mask inclined portion and corresponds to a non-processed portion of the workpiece. And
The modulation mask tilt part is composed of a plurality of phase modulation unit areas, and light emitted after being phase-modulated by the modulation mask tilt part is distributed on the imaging plane of the imaging optical system based on the phase modulation unit areas. Produces
The modulation mask shielding part includes a light shielding layer that shields light,
The phase modulation unit conversion region obtained by converting the phase modulation unit region into the imaging surface of the imaging optical system is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system,
The radius R of the point image distribution range of the imaging optical system is defined as R = 0.61λ / NA, where λ is the center wavelength of light and NA is the numerical aperture on the exit side of the imaging optical system,
The phase modulation unit region includes a first phase modulation unit region having a first phase modulation amount and a second phase modulation unit region having a second phase modulation amount,
Tp 1 occupancy of the first phase modulation unit area in the modulation mask inclined _portion, when the occupation rate of the second phase modulation unit areas and Tp _2, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, modulation A modulation mask characterized in that {absolute value of (Tp ₁ −Tp ₂ )} increases as it moves away from a region adjacent to the modulation mask shielding portion in the mask inclined portion. In the workpiece, at least one inclined portion and a maximum processed portion located on the bottom side of the inclined portion are formed by processing by the processing apparatus,
The modulation mask incorporated in a processing apparatus includes a modulation mask inclination portion that phase-modulates light irradiated to the inclination portion, and a modulation mask that is adjacent to one side of each modulation mask inclination portion and corresponds to the non-processing portion. The modulation mask according to claim 8, further comprising: a shielding portion, and a modulation mask transmission portion corresponding to the maximum processing portion adjacent to the other side of each modulation mask inclined portion. The modulation mask transmission unit includes a plurality of phase modulation unit regions, and light intensity distribution based on the phase modulation unit regions is generated on the imaging plane of the imaging optical system by the light phase-modulated by the modulation mask transmission unit. Which generates
The occupation ratio of the first phase modulation unit area in the modulation mask transmitting section is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation ratio of the first phase modulation unit area in the modulation mask tilt section is Tp. ₁ , when the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied The modulation mask according to claim 9. A modulation mask incorporated in a processing apparatus that forms at least one tapered tapered hole having a through portion or a bottom portion and a tapered portion on the workpiece by irradiating the workpiece with light emitted from a light source. In
The processing equipment
A light source that emits light;
A modulation mask that is provided on an emission side of the light source and that modulates and emits light from the light source; and
An imaging optical system that is provided on the emission side of the modulation mask, forms an image of light modulated by the modulation mask and irradiates the workpiece, and forms an inclined portion on the workpiece;
The modulation mask is positioned at the periphery of each modulation mask transmission portion corresponding to the light irradiated to the through portion or bottom portion of the taper hole, and the light irradiated to the taper portion of the taper hole. A modulation mask inclined part for phase modulation, and a modulation mask shielding part located at the periphery of each modulation mask inclined part,
The modulation mask tilt part is composed of a plurality of phase modulation unit areas, and light emitted after being phase-modulated by the modulation mask tilt part is distributed on the imaging plane of the imaging optical system based on the phase modulation unit areas. Produces
The modulation mask shielding part includes a light shielding layer that shields light,
The phase modulation unit conversion region obtained by converting the phase modulation unit region into the imaging surface of the imaging optical system is smaller in at least one direction than the radius of the point image distribution range of the imaging optical system,
The radius R of the point image distribution range of the imaging optical system is defined as R = 0.61λ / NA, where λ is the center wavelength of light and NA is the numerical aperture on the exit side of the imaging optical system,
The phase modulation unit region includes a first phase modulation unit region having a first phase modulation amount and a second phase modulation unit region having a second phase modulation amount,
Tp 1 occupancy of the first phase modulation unit area in the modulation mask inclined _portion, when the occupation rate of the second phase modulation unit areas and Tp _2, the distribution of Tp ₁ and Tp ₂ in the modulation mask ramps, modulation The distribution is such that {the absolute value of (Tp ₁ −Tp ₂ )} increases from a region adjacent to the modulation mask shielding portion to a region adjacent to the modulation mask transmission portion in the mask inclined portion. Modulation mask. The modulation mask transmission unit includes a plurality of phase modulation unit regions, and light intensity distribution based on the phase modulation unit regions is generated on the imaging plane of the imaging optical system by the light phase-modulated by the modulation mask transmission unit. Which generates
The occupation ratio of the first phase modulation unit area in the modulation mask transmitting section is Cp ₁ , the occupation ratio of the second phase modulation unit area is Cp _2, and the occupation ratio of the first phase modulation unit area in the modulation mask tilt section is Tp. ₁ , when the occupation ratio of the second phase modulation unit region is Tp ₂ , the relationship of {absolute value of (Cp ₁ −Cp ₂ )}> {absolute value of (Tp ₁ −Tp ₂ )} is satisfied The modulation mask according to claim 11.   The modulation mask according to claim 8, wherein the workpiece includes a basic resin and a filler added to the basic resin.   14. The first phase modulation amount in the first phase modulation unit region and the second phase modulation amount in the second phase modulation unit region differ by an odd multiple of 180 degrees. Any one of the modulation masks.

Images