Laser processing method, method for manufacturing a substrate, and laser processing apparatus

Abstract

The present invention provides a laser processing method for using a laser to form a recess and / or through-hole in a workpiece, wherein processing is performed while the laser intensity distribution on a surface to be processed of the workpiece has an irradiation shape where the intensity of a section on the outside of the intensity distribution is greater than the intensity of a section on the inside. This makes it possible to provide a laser processing method which can prevent a recess and / or through-hole to be formed from assuming a tapered shape, and by extension, can form a complex pattern with high definition, even when forming the recess and / or through-hole with high resolution.

Description

Laser processing method, substrate manufacturing method, laser processing device, substrate, and semiconductor package substrate

[0001] The present invention relates to a laser processing method, a substrate manufacturing method, a laser processing apparatus, a substrate, and a semiconductor package substrate.

[0002] Semiconductor package substrates have been actively developed in line with the trend of "More Than More" and the shift to SoC (System on a Chip), which integrates a system into a single chip.

[0003] Furthermore, the configuration of semiconductor package substrates is becoming more complex and denser, and devices using excimer lasers are being used to manufacture the base substrates.

[0004] For example, Patent Document 1 describes a laser processing method for performing shape processing on a workpiece to a predetermined depth position using laser light, characterized in that the laser power of the laser light and the relative movement speed between the workpiece and the laser light are increased so that the energy per unit length of the laser light, which is optimally set according to the workpiece, falls within an energy range that does not allow the laser light to penetrate the workpiece even when the laser power increases due to power fluctuations in a laser light oscillator, and the number of irradiations required for laser processing is reduced.

[0005] Patent Document 2 also describes a laser processing method for processing an excavation area of ​​a workpiece by sequentially irradiating the excavation area with laser light having a small beam cross-section relative to the excavation area, the method comprising: a first processing step in which the entire excavation area is sequentially irradiated with laser light having a beam cross-section of a first shape and forming a first irradiation area on the workpiece corresponding to the beam cross-section of the first shape; and a second processing step in which the excavation area is sequentially irradiated with laser light having a beam cross-section of a second shape smaller than the first shape and forming a second irradiation area on the workpiece corresponding to the beam cross-section of the second shape. In the first processing step, the laser light forming the first irradiation area is sequentially irradiated so as to form an overlapping area in which parts of the first irradiation area overlap each other, and in the second processing step, the laser light forming the second irradiation area is sequentially irradiated so that the second irradiation area is included in an area of ​​the excavation area other than the overlapping area.

[0006] Also, Non-Patent Document 1 introduces the formation of high-quality, high-aspect Si through-holes using a Bessel beam.

[0007] Patent Document 1: JP 2009-22978 A International Publication No. WO2013 / 094025

[0008] Koji Sugioka, "High-quality, high-aspect-ratio silicon through-hole formation using optimized ultrashort pulse Bessel beams," FORM TECH REVIEW 2016, VOL. 26

[0009] Conventionally, recesses formed by laser processing have had the problem that the higher the resolution, the smaller the width of the bottom of the recess than the width of the opening of the recess on the initial processing surface, i.e., the tapered tip. The same problem has also been found in conventional through holes, where the higher the resolution, the smaller the width of the bottom opening of the through hole than the width of the top end of the through hole, i.e., the tapered tip. Furthermore, the formation of such tapered recesses and / or through holes is inconvenient for forming high-resolution, complex patterns (e.g., circuit patterns). In particular, in semiconductor package substrate applications, metal wiring may be embedded in the processed recesses, which can result in high wiring resistance when high-resolution patterns are created. To prevent this, processing that achieves a deep processing depth and a wide width all the way to the bottom is required. Performing such processing enables the production of high-quality semiconductor package substrates with low wiring resistance.

[0010] The present invention has been made to solve the above problems, and aims to provide a laser processing method that can prevent the recesses and / or through holes from becoming tapered even when forming recesses and / or through holes at high resolution, and thereby form high-definition, complex patterns; a substrate manufacturing method that can manufacture a substrate having a high-definition, complex pattern; a laser processing apparatus that can prevent the recesses and / or through holes from becoming tapered even when forming recesses and / or through holes at high resolution, and can provide a high-quality semiconductor package substrate with low wiring resistance, and thereby form high-definition, complex patterns; a substrate that can realize a high-definition, complex wiring pattern; a substrate that can realize a VIA electrode pattern with reduced tapering from the front surface to the back surface; a semiconductor package substrate having a high-definition, complex metal wiring pattern; and a semiconductor package substrate having a VIA electrode pattern with reduced tapering from the front surface to the back surface.

[0011] In order to solve the above problems, the present invention provides a laser processing method for forming recesses and / or through holes in a workpiece using a laser, wherein the laser intensity distribution on the workpiece surface is set to an irradiation shape in which the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part.

[0012] With this laser processing method, even when recesses are formed with high resolution, the width of the bottom of the recess can be prevented from being smaller than the width of the opening of the recess on the initial processing surface. Furthermore, with this laser processing method, even when through holes are formed with high resolution, the width of the opening at the bottom of the through hole can be prevented from being smaller than the width at the top of the through hole. In other words, with the laser processing method of the present invention, even when recesses and / or through holes are formed with high resolution, the recesses and / or through holes formed can be prevented from having a tapered shape, and thus high-resolution, complex patterns can be formed.

[0013] For example, as the processing progresses in the depth direction of the workpiece, the shape of the intensity distribution of the laser on the processing surface of the workpiece can be changed to perform processing.

[0014] In this way, the laser intensity distribution may be changed as the processing progresses in the depth direction of the workpiece. However, in the present invention, it is sufficient to perform processing by setting the laser intensity distribution on at least one processing surface of the workpiece to an irradiation shape in which the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part, and it is not necessarily necessary to change the laser intensity distribution continuously.

[0015] In this case, as the processing progresses in the depth direction of the workpiece, the shape of the intensity distribution of the laser may be changed so that the intensity of the outer portion in the intensity distribution of the laser becomes greater than the intensity of the inner portion.

[0016] By carrying out the processing in this manner, it is possible to more reliably prevent the recesses and / or through holes to be formed from having a tapered shape, and it is therefore possible to more reliably form high-definition and complex patterns.

[0017] For example, by passing a laser having an intensity distribution in which the laser intensity is greatest at the center and lowest at the base through a prism, processing may be performed by changing the shape of the intensity distribution of the laser so that the intensity of the outer portion of the laser intensity distribution becomes greater than the intensity of the inner portion as processing progresses in the depth direction of the workpiece.

[0018] There are no particular limitations on the means for changing the laser irradiation shape so that the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part, but for example, the laser irradiation shape can be changed through a prism.

[0019] In this case, for example, the prism may include a roof prism or a conical prism.

[0020] For example, a prism including a roof prism or a conical prism may be used to form the laser irradiation shape such that the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion.

[0021] The present invention also provides a laser processing method for forming a recess and / or a through-hole in a workpiece using a laser, the method using an optical system that shapes the laser irradiation shape into a top-hat irradiation shape, in which the intensity of the outer portion is greater than the intensity of the inner portion in the intensity distribution of the laser.

[0022] By laser processing a workpiece using such an optical system, at least a portion of the workpiece away from the surface can be processed with a laser irradiation shape in which the intensity of the laser is greater in the outer portion than in the inner portion. With this laser processing method, even when recesses are formed with high resolution, the width of the bottom of the recess can be prevented from being smaller than the width of the opening of the recess on the initial processing surface. Furthermore, with this laser processing method, even when through holes are formed with high resolution, the width of the opening at the lower end of the through hole can be prevented from being smaller than the width of the opening at the upper end of the through hole. In other words, with the laser processing method of the present invention, even when recesses and / or through holes are formed with high resolution, the recesses and / or through holes formed can be prevented from having a tapered shape, thereby enabling the formation of high-resolution, complex patterns.

[0023] For example, the initial processing surface of the workpiece may be processed with a laser having the top-hat irradiation shape, and at least a portion of the workpiece excluding the initial processing surface may be processed with a laser having an irradiation shape in which the intensity of the outer portion is greater than the intensity of the inner portion.

[0024] In this way, the initial processing surface of the workpiece may be processed with a laser having a top-hat irradiation shape.

[0025] For example, a substrate for a semiconductor package may be processed as the workpiece to form recesses and / or through holes in the substrate for a semiconductor package.

[0026] The workpiece is not particularly limited, but may be, for example, a semiconductor package substrate.

[0027] In particular, when processing semiconductor package substrates, there are processing patterns that include a mixture of through holes, recesses, for example, via processing and groove processing. In this case, the method of the present invention allows processing in the same process without separating the via processing and groove processing steps. Furthermore, as semiconductor package substrates become increasingly dense, the conventional laser drill method for via processing increases the processing time due to the increased number of holes drilled as a result of the increased density. However, with this method, there is no increase in processing time due to the increased number of holes drilled or the increased fineness of the pattern.

[0028] For example, the laser may be generated by using an excimer laser oscillator.

[0029] The laser light source is not particularly limited, but for example, an excimer laser oscillator can be used. By using an excimer laser, it is possible to efficiently process workpieces made of organic materials, such as ABF substrates, and to achieve high-productivity processing. In addition, because the excimer laser has low coherence, it is possible to form an extremely uniform beam by using an excimer laser.

[0030] The laser may be irradiated onto the workpiece through a photomask.

[0031] The laser processing of the present invention can also be carried out using a photomask.

[0032] Processing may be performed while scanning the laser relatively over the surface to be processed.

[0033] The laser processing of the present invention can also be scanning processing.

[0034] For example, ablation processing can be performed.

[0035] According to the laser processing method of the present invention, for example, ablation processing can be performed.

[0036] For example, the recesses and / or through holes can be formed to have a width of 20 μm or less.

[0037] According to the laser processing method of the present invention, it is possible to form a highly precise pattern including recesses and / or through holes having a width of 20 μm or less.

[0038] For example, the recesses and / or through holes may be formed to have a depth of 20 μm or less.

[0039] According to the laser processing method of the present invention, it is also possible to form a highly precise pattern including recesses and / or through holes having a depth of 20 μm or less.

[0040] The recesses and / or through holes may be formed such that the ratio of the height of the processed portion to the width of the bottom of the recess or the width of the lower opening of the through hole is 1.0 or greater.

[0041] According to the laser processing method of the present invention, recesses and / or through holes with such a high aspect ratio can be formed.

[0042] The recess can be formed so that the width of the bottom of the recess is 70% or more of the opening width of the recess on the initial processing surface of the workpiece, and / or the through hole can be formed so that the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the initial processing surface of the workpiece.

[0043] According to the laser processing method of the present invention, for example, a recess can be formed in which the width of the bottom of the recess is 70% or more of the opening width of the recess on the initial processing surface of the workpiece, and / or a through hole in which the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the initial processing surface of the workpiece.

[0044] A plurality of recesses may be formed, and the distance between the bottoms of adjacent recesses may be set to 110% or less of the width of the bottoms.

[0045] According to the laser processing method of the present invention, a plurality of recesses can also be formed at high density.

[0046] The present invention also provides a method for manufacturing a substrate having the recesses and / or through holes, which includes forming the recesses and / or through holes in the substrate, which is the workpiece, by the laser processing method of the present invention.

[0047] As described above, the laser processing method of the present invention is capable of forming a highly precise and complex pattern. Therefore, the substrate manufacturing method of the present invention, which includes the laser processing method of the present invention, makes it possible to manufacture a substrate having a highly precise and complex pattern.

[0048] The present invention also provides a laser processing device that uses a laser to form recesses and / or through holes in a workpiece, comprising: a laser light source that oscillates the laser; and an optical system that sets an irradiation shape of the laser such that the intensity distribution of the laser on the workpiece surface is such that the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part.

[0049] By using such a laser processing device, even when recesses are formed at high resolution, the width of the bottom of the recess can be prevented from being smaller than the width of the opening of the recess on the initial processing surface. Furthermore, by using such a laser processing device, even when through holes are formed at high resolution, the width of the lower opening of the through hole can be prevented from being smaller than the width of the upper end of the through hole. In other words, with the laser processing device of the present invention, even when recesses and / or through holes are formed at high resolution, it is possible to prevent the recesses and / or through holes from having a tapered shape, thereby enabling the formation of high-resolution, complex patterns.

[0050] The optical system preferably comprises: a prism that converts a laser having an intensity distribution in which the laser intensity is greatest at the center and lowest at the base into a laser having an irradiation shape in which the intensity of the outer portion of the laser intensity distribution is greater than the intensity of the inner portion; and a shaping optical system that converts the irradiation shape of the laser converted by the prism into a top-hat shaped irradiation shape.

[0051] The optical system may include, for example, the prism and the shaping optical system.

[0052] In this case, for example, the prism may include a roof prism or a conical prism.

[0053] For example, a prism including a roof prism or a conical prism may be used to form the laser irradiation shape such that the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion.

[0054] The laser light source preferably comprises an excimer laser oscillator.

[0055] The laser light source is not particularly limited, but for example, an excimer laser oscillator can be used. By using an excimer laser, it is possible to efficiently process workpieces made of organic materials, such as ABF substrates, and to achieve highly productive processing. In addition, the excimer laser has low coherence, making it possible to form an extremely uniform beam.

[0056] The apparatus may further include a stage on which the workpiece is placed, and a photomask disposed between the optical system and the stage.

[0057] The laser processing apparatus of the present invention can also be equipped with such a stage and photomask.

[0058] In this case, the apparatus may further include a controller configured to move the workpiece placed on the stage and the photomask in synchronization.

[0059] The laser processing apparatus of the present invention can also be equipped with such a controller.

[0060] The present invention also provides, as a first embodiment of the substrate, a substrate used for a semiconductor package substrate, having at least two recesses on the surface of the substrate that are adjacent to each other in a cross section perpendicular to the surface, the distance between the bottoms of the recesses in the cross section being 110% or less of the width of the bottoms of the recesses, the depth of the recesses in the cross section being 20 μm or less, and the ratio of the depth of the recesses to the width of the bottoms of the recesses in the cross section being 1.0 or more.

[0061] Such substrates can realize highly precise and complex wiring patterns by incorporating wiring into the recesses.

[0062] The width of the bottom of the recess is preferably 70% or more of the opening width of the recess on the surface.

[0063] Such a substrate allows for wiring patterns with low wiring resistance when wiring is incorporated into the recesses. In addition, the contact area at the interface between the wiring and the substrate can be increased, making it less likely for problems such as wiring peeling to occur.

[0064] The opening width of the recess on the surface is preferably 20 μm or less.

[0065] Such a substrate allows for a finer wiring pattern to be realized.

[0066] The ratio of the depth of the recess to the width of the bottom of the recess in the cross section may be 1.1 or greater.

[0067] Alternatively, the ratio of the depth of the recess to the width of the bottom of the recess may be 1.5 or greater.

[0068] Alternatively, the ratio of the depth of the recess to the width of the bottom of the recess may be 2.4 or greater.

[0069] Alternatively, the ratio of the depth of the recess to the width of the bottom of the recess may be 3.4 or greater.

[0070] In the substrate of the first embodiment, the ratio of the depth of the recess to the width of the bottom of the recess may be 1.0 or greater, for example, 1.1 or greater, 1.5 or greater, 2.4 or greater, or 3.4 or greater.

[0071] For example, the substrate may have a bottom width of the recess that is 70% or more of the opening width of the recess, and a ratio of the depth of the recess to the bottom width of the recess that is 2.4 or more.

[0072] Such a substrate makes it possible to more reliably realize high-definition, low-resistance wiring patterns. In addition, the contact area at the interface between the wiring and the substrate can be increased, making it less likely for problems such as peeling of the wiring to occur.

[0073] The recess may include a trench.

[0074] The recesses may include, for example, trenches extending in a direction parallel to the surface of the substrate, or may be fastening holes having a circular or rectangular planar shape.

[0075] The substrate may have a back surface opposite to the front surface, and may further have a through-hole penetrating from the front surface to the back surface.

[0076] With such a substrate, a package substrate further having a VIA electrode pattern can be realized.

[0077] For example, the width of the upper opening of the through hole on the surface can be 20 μm or less.

[0078] Such a substrate makes it possible to realize a high-definition, high-density via electrode pattern.

[0079] The ratio of the processed length of the through hole to the width of the lower end opening of the through hole on the back surface can be 1.0 or more.

[0080] The ratio of the processed length to the width of the lower opening of the through hole is not particularly limited, but can be, for example, 1.0 or more.

[0081] The width of the lower opening of the through hole on the rear surface is preferably 70% or more of the width of the upper opening of the through hole on the front surface.

[0082] With such a substrate, it is possible to realize a VIA electrode pattern in which the tapering from the front surface to the back surface is suppressed.

[0083] It is preferable that the ratio of the processing length of the through hole to the width of the lower opening of the through hole on the back surface is 1.0 or more, and the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the front surface.

[0084] Such a substrate can realize a highly precise VIA electrode pattern with reduced tapering from the front surface to the back surface.

[0085] For example, the width of the bottom of the recess may be 70% or more of the opening width of the recess, the ratio of the depth of the recess to the width of the bottom of the recess may be 2.4 or more, the ratio of the processing length of the through hole to the width of the lower end opening of the through hole on the back surface may be 1.0 or more, and the width of the lower end opening of the through hole may be 70% or more of the width of the upper end opening of the through hole on the front surface.

[0086] With such a substrate, it is possible to more reliably realize a high-definition wiring pattern and a VIA electrode pattern that are less tapered from the front surface to the back surface.

[0087] The present invention also provides a semiconductor package substrate according to a first aspect, which is a semiconductor package substrate including the substrate according to the first aspect of the present invention, in which metal wiring is embedded in the recess.

[0088] Such a semiconductor package substrate makes it possible to realize a semiconductor package having a highly precise, high-density, and complex metal wiring pattern.

[0089] The present invention also provides, as a second aspect of the substrate, a substrate used for a semiconductor package substrate, having a through hole penetrating from a front surface of the substrate to a back surface opposite the front surface, and the width of the lower opening of the through hole on the back surface is 70% or more of the width of the upper opening of the through hole on the front surface.

[0090] With such a substrate of the second aspect, it is possible to realize a semiconductor package having a VIA electrode pattern in which tapering from the front surface to the back surface is suppressed.

[0091] The width of the upper opening of the through hole on the surface is preferably 20 μm or less.

[0092] Such a substrate makes it possible to realize a semiconductor package having a highly precise, high-density, and complex VIA electrode pattern with reduced tapering from the front surface to the back surface.

[0093] A ratio of a processed length of the through hole to a width of a lower end opening of the through hole on the rear surface may be 1.0 or more.

[0094] In the substrate of the second aspect, the ratio of the processed length of the through-hole to the width of the lower end opening can be set to, for example, 1.0 or more.

[0095] The present invention also provides a semiconductor package substrate of a second aspect, which is a semiconductor package substrate that includes a substrate of the first aspect that includes a through hole, or a substrate of the second aspect, in which the through hole is subjected to VIA processing.

[0096] The semiconductor package substrate of the second aspect can have a highly precise, high-density, and complex VIA electrode pattern with reduced tapering from the front surface to the back surface.

[0097] As described above, with the laser processing method of the present invention, even when recesses and / or through holes are formed with high resolution, it is possible to prevent the recesses and / or through holes from having a tapered shape, and thus it is possible to form high-resolution, complex patterns.

[0098] Furthermore, the substrate manufacturing method of the present invention makes it possible to manufacture substrates having highly precise and complex patterns.

[0099] With the laser processing apparatus of the present invention, even when recesses and / or through holes are formed with high resolution, the recesses and / or through holes formed can be prevented from becoming tapered, and it is possible to provide a high-quality semiconductor package substrate with low wiring resistance, which in turn makes it possible to form high-resolution, complex patterns.

[0100] In the substrate according to the first aspect of the present invention, by incorporating wiring into the recesses, a highly precise, high-density and complex wiring pattern can be realized.

[0101] The semiconductor package substrate according to the first aspect of the present invention makes it possible to realize a semiconductor package having a highly precise, high-density, and complex metal wiring pattern.

[0102] The substrate according to the second aspect of the present invention makes it possible to realize a semiconductor package having a VIA electrode pattern in which tapering from the front surface to the back surface is suppressed.

[0103] The semiconductor package substrate according to the second aspect of the present invention can have a VIA electrode pattern in which tapering from the front surface to the back surface is suppressed.

[0104] 9 is a schematic diagram showing an example of a laser processing apparatus of the present invention; FIG. 10 is a schematic diagram showing an example of laser irradiation in the laser processing method of the present invention; FIG. 11 is a schematic diagram showing out-focus of the laser irradiation in FIG. 2; FIG. 12 is a schematic diagram showing an example of the laser processing method of the present invention; FIG. 13 is a schematic diagram showing another example of laser irradiation in the laser processing method of the present invention; FIG. 14 is a schematic cross-sectional view showing an example of a recess that can be formed by the laser processing method of the present invention; FIG. 15 is an intensity distribution of an example of a laser that can be used in the laser processing method of the present invention; FIG. 16 is a schematic diagram showing an example of a conventional laser processing apparatus; FIG. 17 is a schematic diagram showing an example of laser irradiation in the conventional laser processing method; FIG. 18 is a schematic diagram showing out-focus of the laser irradiation in FIG. 9; FIG. 19 is a schematic diagram showing an example of the conventional laser processing method; FIG. 10 is a schematic cross-sectional view showing another example of laser irradiation in the conventional laser processing method; FIG. 11 is a schematic cross-sectional view showing an example of a recess that can be formed by the conventional laser processing method; FIG. 12 is a schematic partial cross-sectional view of an example of a substrate of the first embodiment of the present invention; FIG. 13 is a schematic partial perspective view of another example of the substrate of the first embodiment of the present invention; FIG. 14 is a schematic partial cross-sectional view of another example of the substrate of the first embodiment of the present invention; FIG. 10 is a schematic plan view of another example of a semiconductor package substrate of the present invention.

[0105] As described above, there has been a demand for the development of a laser processing method that can prevent the recesses and / or through holes from becoming tapered even when recesses and / or through holes are formed at high resolution, thereby enabling the formation of high-definition, complex patterns; a substrate manufacturing method that can manufacture substrates having high-definition, complex patterns; and a laser processing apparatus that can prevent the recesses and / or through holes from becoming tapered even when recesses and / or through holes are formed at high resolution, thereby enabling the formation of high-definition, complex patterns.

[0106] As a result of extensive research into the above-mentioned problems, the inventors have discovered a laser processing method for forming recesses and / or through holes in a workpiece using a laser, in which the laser intensity distribution on the workpiece surface is processed in an irradiation shape in which the intensity of the outer parts of the intensity distribution is greater than the intensity of the inner parts, and thereby, even when recesses and / or through holes are formed with high resolution, the recesses and / or through holes formed can be prevented from having a tapered shape, and thus high-resolution, complex patterns can be formed, thereby completing the present invention.

[0107] That is, the present invention is a laser processing method for forming a recess and / or a through hole in a workpiece using a laser, in which the intensity distribution of the laser on the workpiece surface is set to an irradiation shape in which the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part.

[0108] The present invention also provides a laser processing method for forming a recess and / or a through hole in a workpiece using a laser, the method using an optical system that shapes the laser irradiation shape into a top-hat irradiation shape, in which the intensity of the outer portion is greater than the intensity of the inner portion in the intensity distribution of the laser.

[0109] The present invention also provides a method for manufacturing a substrate having the recesses and / or through holes, which includes forming the recesses and / or through holes in the substrate, which is the workpiece, by the laser processing method of the present invention.

[0110] The present invention also provides a laser processing device that uses a laser to form recesses and / or through holes in a workpiece, comprising: a laser light source that oscillates the laser; and an optical system that sets an irradiation shape of the laser such that the intensity distribution of the laser on the workpiece surface is such that the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion.

[0111] The present invention also relates to a first embodiment of a substrate used in a semiconductor package substrate, the substrate having at least two recesses on its surface that are adjacent to each other in a cross section perpendicular to the surface, the distance between the bottoms of the recesses in the cross section being 110% or less of the width of the bottoms of the recesses, the depth of the recesses in the cross section being 20 μm or less, and the ratio of the depth of the recesses to the width of the bottoms of the recesses in the cross section being 1.0 or greater.

[0112] The present invention also provides a semiconductor package substrate including the substrate according to the first aspect of the present invention, wherein metal wiring is embedded in the recess.

[0113] The present invention also relates to a second aspect of a substrate used in a semiconductor package substrate, the substrate having a through hole penetrating from a front surface of the substrate to a back surface opposite the front surface, wherein the width of a lower opening of the through hole on the back surface is 70% or more of the width of an upper opening of the through hole on the front surface.

[0114] The present invention is a semiconductor package substrate that includes a substrate of the first aspect that includes a through hole, or a substrate of the second aspect, in which the through hole is a semiconductor package substrate of the second aspect that has been subjected to VIA processing.

[0115] The present invention will be described in detail below, but the present invention is not limited thereto.

[0116] [Laser Processing Apparatus] Fig. 1 is a schematic diagram showing an example of a laser processing apparatus of the present invention. The laser processing apparatus 100 shown in Fig. 1 is a laser processing apparatus 100 that uses a laser to form a recess and / or a through hole in a workpiece 70. Note that, although the laser processing apparatus 100 shown in Fig. 1 is an example of the laser processing apparatus of the present invention, the laser processing apparatus of the present invention is not limited to the apparatus shown in Fig. 1.

[0117] The laser processing apparatus 100 shown in FIG. 1 includes a laser light source 10 that oscillates a laser 1, and an optical system 20 that converts the intensity distribution and irradiation shape of the laser 1 on the processing surface of a workpiece 70.

[0118] In the laser processing apparatus 100 shown in Fig. 1, the optical system 20 includes a prism 21 and a shaping optical system 22. As will be described in detail below, the prism 21 is a prism that converts a laser having an intensity distribution in which the laser intensity is greatest in the center and lowest at the base into a laser having an irradiation shape in which the intensity of the outer portion of the laser intensity distribution is greater than the intensity of the inner portion, and the shaping optical system 22 is a shaping optical system that converts the irradiation shape of the laser converted by the prism 21 into a top-hat irradiation shape. In the laser processing apparatus 100 shown in Fig. 1, the prism 21 includes a roof prism, but may also include a conical prism.

[0119] The laser processing apparatus 100 shown in FIG. 1 further includes a photomask 30, a folding mirror 40, and a reduction projection optical system 50 in this order on the optical path of the laser processing apparatus 100 from the optical system 20 to the workpiece 70.

[0120] The laser processing apparatus 100 further includes a stage 60 on which the workpiece 70 is placed, and a controller 80 electrically connected to the photomask 30 and the stage 60. In another aspect, the laser processing apparatus 100 further includes the stage 60 on which the workpiece 70 is placed, and a photomask 30 disposed between the optical system 20 and the stage 60.

[0121] The photomask 30, the folding mirror 40, the reduction projection optical system 50, the stage 60, and the controller 80 are optional components for the laser processing apparatus 100 of the present invention.

[0122] The light source 10 that oscillates the laser 1 is, for example, a light source (laser oscillator) 10 that irradiates (emits) the pulsed laser 1. More specifically, the laser light source 10 shown in Fig. 1 includes an excimer laser oscillator.

[0123] 1 also includes a mask alignment camera 31 as an imaging means for reading characteristic portions of the photomask 30, and a workpiece alignment camera 61 as an imaging means for reading characteristic portions of the workpiece 70. The mask alignment camera 31 is configured to send position information of the characteristic portions of the photomask 30 to the controller 80. The workpiece alignment camera 61 is configured to send position information of the characteristic portions of the workpiece 70 to the controller 80. The controller 80 is configured to adjust the relative positions of the workpiece 70 and the photomask 30 based on this position information. In another aspect, the controller 80 is configured to synchronously move the workpiece 70 and the photomask 30 placed on the stage 60.

[0124] [Laser Processing Method] The laser processing method of the present invention can be carried out using, for example, the laser processing apparatus of the present invention, but can also be carried out using an apparatus other than the laser processing apparatus of the present invention.

[0125] An example of the laser processing method of the present invention that can be performed using the laser processing apparatus 100 shown in FIG. 1 will be specifically described below.

[0126] The laser processing method of the present invention is a laser processing method for forming recesses and / or through holes in a workpiece 70 using a laser.

[0127] In the laser processing of the present invention, the laser intensity distribution on the processing surface of the workpiece 70 is set to an irradiation shape in which the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion. Such a laser processing method will be described by way of an example with reference to FIGS. 1 to 4.

[0128] First, as shown in Fig. 1, a laser 1 having the irradiation shape shown in Fig. 1(a) is emitted from a laser light source 10. In this example, the irradiation shape of the laser 1 is an irradiation shape with an intensity distribution in which the laser intensity in the inner portion 1a is greater than the laser intensity in the outer portion 1b, as shown in Fig. 2. In another aspect, the irradiation shape of the laser 1 has an intensity distribution in which the laser intensity is greatest in the center (inner portion) 1a and is smaller at the skirt (outer portion) 1b.

[0129] Next, the laser 1 is incident on a prism 21 of the optical system 20. The prism 21 converts the laser 1 into a laser 2 having an irradiation shape (FIG. 1(b)) in which the intensity of the outer portion of the intensity distribution of the laser 1 is greater than the intensity of the inner portion. FIG. 1 shows a prism 21 made up of four (two pairs of) roof prisms as an example of the prism 21. Note that FIG. 2 shows only two roof prisms 21a and 21b of the laser 1 that are involved in the irradiation shape of the surface parallel to the paper surface.

[0130] The prism 21 is not limited to a roof prism, and may be, for example, a conical prism.

[0131] Non-Patent Document 1 discloses the use of an axicon lens, which is a conical prism, but does not mention anything about a prism that converts the laser into an irradiation shape in which the intensity of the outer part of the laser intensity distribution is greater than the intensity of the inner part.

[0132] Next, the laser 2, which is emitted from the prism 21 and has the irradiation shape shown in Figures 1(b) and 2, enters the shaping optical system 22. As shown in Figure 2, the shaping optical system 22 focuses each component of the laser 2 toward the image formation point F1, and shapes the irradiation shape of the laser 2 into a top-hat irradiation shape shown in Figure 1(c), thereby forming the laser 3.

[0133] The laser 3 is incident on the photomask 30 located at the position of the image forming point F1. The photomask 30 has a mask pattern corresponding to the pattern to be machined on the workpiece 70. By scanning and irradiating the laser onto the workpiece 70 via the photomask 30, recesses and / or through-holes can be formed in the workpiece 70 in the desired pattern.

[0134] The laser beam 4 emitted from the photomask 30 and having the irradiation shape (top hat shape) shown in Fig. 1(d) is redirected by a folding mirror 40 and enters a reduction projection optical system (projection lens) 50. The effect of using an optional reduction projection optical system 50 will be described later.

[0135] 2, the laser beam 5 emitted from the reduction projection optical system 50 reaches the surface (initial processing surface) 71 of the workpiece 70. In FIG. 2, an example is shown in which the image forming point F2 of the reduction projection optical system 50 is aligned with the surface 71 of the workpiece 70. However, the image forming point F2 of the reduction projection optical system 50 is not limited to the surface 71 of the workpiece 70.

[0136] As shown in Fig. 2, the irradiation shape of the laser 5 irradiated onto the surface 71 of the workpiece 70 is a top hat shape as shown in Fig. 1(e) and Fig. 2. On the other hand, at the workpiece surface 72 where processing has progressed further from the image point F2, processing is performed with the intensity distribution of the laser 6 set to an irradiation shape in which the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a, as shown in Fig. 2.

[0137] 1 and 2, as shown in outline in Figures 3(a) to 3(e), the further away from the image formation point F2 (under focus U), the closer the irradiation shape of the laser 6 becomes to the irradiation shape of the laser 2 before shaping by the shaping optical system 22. This is the reason why the intensity distribution of the laser 6 has a greater intensity in the outer portion 6b of the intensity distribution than in the inner portion 6a.

[0138] The laser processing method of the present invention processes the workpiece surface 72 by setting the intensity distribution of the laser 6 to an irradiation shape in which the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a, thereby preventing the recess 200 from tapering, as shown schematically in FIG. 4 . By continuing processing, a through hole with reduced tapering can be formed. That is, the laser processing method of the present invention allows for deeper digging without tapering as processing progresses. Furthermore, the laser processing method of the present invention can prevent the recess and / or through hole from tapering in this way, allowing for the formation of high-resolution, complex patterns. Furthermore, the laser processing method of the present invention can prevent the recess 200 and / or through hole from tapering, even when forming the recess and / or through hole with high resolution.

[0139] On the other hand, as will be explained below with reference to Figures 8 to 11, if the laser intensity distribution on the workpiece surface is not configured to have an irradiation shape in which the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part, it is impossible to prevent the recesses and / or through holes to be formed from having a tapered shape.

[0140] Fig. 8 is a schematic diagram showing an example of a conventional laser processing apparatus. The laser processing apparatus 100' shown in Fig. 8 is similar to the laser processing apparatus 100 shown in Fig. 1 except that it does not include the prism 21.

[0141] In the laser processing apparatus 100′ shown in FIGS. 8 and 9, a laser beam 1 oscillates from the laser light source 10 and has the irradiation shape shown in FIG. 8(a). The laser beam 1 enters the shaping optical system 22 and becomes a laser beam 3′ having the top-hat irradiation shape shown in FIG. 8(b). The laser beam 3′ passes through the photomask 30 at the image point F1 of the shaping optical system 22 and becomes a laser beam 4′ having the top-hat irradiation shape shown in FIG. 8(c). The direction of the laser beam 4′ is changed by the folding mirror 40 and enters the reduction projection optical system 50. The laser beam 5′ exits the reduction projection optical system 50 and has the top-hat irradiation shape shown in FIG. 8(d). The laser beam 5′ reaches the surface 71 of the workpiece 70 located at the image point F2 of the reduction projection optical system 50.

[0142] Next, as the processing progresses and the processing surface 72 moves away from the surface 71 of the workpiece 70 (underfocus U), the irradiation shape of the laser 6' approaches the irradiation shape of the laser 1 emitted from the laser light source 10, as shown in Figures 10(a) to 10(e). Therefore, when processing the processing surface 72 located away from the surface 71 of the workpiece 70, the intensity distribution of the laser 6' does not have an irradiation shape in which the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part, as shown in Figure 10.

[0143] When laser processing is performed using this method, the recesses and / or through holes formed have a tapered shape, as shown in Fig. 11. In particular, when recesses and / or through holes are formed with high resolution, the tapering becomes significant, making it impossible to process a high aspect ratio.

[0144] In the laser processing method of the present invention, processing may be performed on at least a portion of a processing surface 72 of a workpiece 70 using a laser having an irradiation shape in which the intensity of an outer portion 6b is greater than the intensity of an inner portion 6a. For example, as shown in the example of Figures 1 and 2, a surface (initial processing surface) 71 of the workpiece 70 may be processed using a laser 5 having a top-hat irradiation shape.

[0145] In the present invention, as shown in FIG. 4, for example, as the processing progresses in the depth direction of the workpiece 70, the shape of the intensity distribution of the laser 6 on the processing surface 72 of the workpiece 70 can be changed to perform processing.

[0146] From another perspective, the example of Figure 4 can also be said to be an example of processing in which the shape of the intensity distribution of the laser 6 is changed so that the intensity of the outer portion 6b in the intensity distribution of the laser 6 becomes greater than the intensity of the inner portion 6a as processing progresses in the depth direction of the workpiece 70.

[0147] By carrying out the processing in this manner, it is possible to more reliably prevent the recesses and / or through holes to be formed from having a tapered shape, and it is therefore possible to more reliably form high-definition and complex patterns.

[0148] However, in the present invention, processing can be performed by setting the intensity distribution of the laser 6 on at least one workpiece surface 72 of the workpiece 70 to an irradiation shape in which the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a, and there is no need to continuously change the laser intensity distribution.

[0149] In the present invention, a photomask 30 can also be used to form a pattern of predetermined recesses and / or through holes. Even when the photomask 30 is used, the intensity distribution of the laser 6 on the processing surface 72 of the workpiece 70 can be shaped so that the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a. This prevents the recesses and / or through holes from becoming tapered, thereby ensuring the formation of a highly precise and complex pattern. Alternatively, as shown in FIG. 5, the present invention does not require the use of a photomask 30.

[0150] On the other hand, even when the photomask 30 is used, unless the processing is performed with an irradiation shape in which the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a, the recesses and / or through holes formed will have a tapered shape, as in the example shown in Fig. 11. Similarly, even when the photomask 30 is not used, unless the processing is performed with an irradiation shape in which the intensity of the outer portion 6b of the intensity distribution is greater than the intensity of the inner portion 6a, as shown in Fig. 12, the recesses and / or through holes formed will have a tapered shape, as in the example shown in Fig. 11.

[0151] In another aspect, the example described with reference to FIGS. 1 to 4 can also be said to be a laser processing method for forming recesses and / or through holes in a workpiece 70 using a laser, which uses an optical system 20 to convert laser 1 into laser 2 having an irradiation shape with an intensity distribution in which the intensity of the outer portion is greater than the intensity of the inner portion, and further to shape it into laser 3 having a top-hat irradiation shape.

[0152] By laser processing the workpiece 70 using such an optical system 20, at least a portion of the workpiece 70 away from the surface can be processed with a laser 6 irradiation shape in which the intensity of the outer portion 6b is greater than the intensity of the inner portion 6a. With this laser processing method, even when recesses are formed with high resolution, the width of the bottom of the recess can be prevented from being smaller than the width of the opening of the recess on the initial processing surface 71. Furthermore, with this laser processing method, even when through holes are formed with high resolution, the width of the lower opening of the through hole can be prevented from being smaller than the width of the upper end of the through hole. In other words, with the laser processing method of the present invention expressed in this aspect, even when recesses and / or through holes are formed with high resolution, the recesses and / or through holes formed can be prevented from having a tapered shape, thereby enabling the formation of high-resolution, complex patterns.

[0153] The workpiece 70 that is the object of laser processing in the present invention is not particularly limited, but for example, a semiconductor package substrate can be used as the workpiece 70.

[0154] In particular, when processing semiconductor package substrates, there are processing patterns that include a mixture of through holes, recesses, for example, via processing and groove processing. In this case, the method of the present invention allows processing in the same process without separating the via processing and groove processing steps. Furthermore, as semiconductor package substrates become increasingly dense, the conventional laser drill method for via processing increases the processing time due to the increased number of holes drilled as a result of the increased density. However, with this method, there is no increase in processing time due to the increased number of holes drilled or the increased fineness of the pattern.

[0155] According to the present invention, for example, ablation processing can be performed on the workpiece 70. In the ablation processing, the laser settings can be freely set within the wavelength and energy density that allow ablation processing, within the range in which the energy of the lasers 5 and 6 is absorbed by the workpiece 70.

[0156] As described above, the present invention makes it possible to form highly precise patterns of recesses and / or through holes. Specifically, the present invention makes it possible to form recesses and / or through holes having a width of, for example, 20 μm or less and in which tapering is suppressed. In contrast, the conventional laser processing apparatus 100′ shown in FIGS. 8 to 12 has difficulty forming recesses and / or through holes having a width of 20 μm or less and in which tapering is suppressed.

[0157] Furthermore, the recesses and / or through holes that can be formed by the present invention can have a depth of, for example, 20 μm or less. Note that recesses can be formed by making the processing depth smaller than the thickness of the workpiece 70, and through holes can be formed by making the processing depth the same as the thickness of the workpiece 70.

[0158] In another aspect, the present invention makes it possible to form a pattern of recesses and / or through holes with a high aspect ratio. For example, the present invention makes it possible to form recesses in which the ratio of the height of the processed portion to the width of the bottom of the recess is 1.0 or more. Furthermore, the present invention makes it possible to form recesses in which the ratio of the height of the processed portion to the width of the lower opening of the through hole is 1.0 or more. In contrast, with the conventional laser processing apparatus 100' shown in Figures 8 to 12, it is difficult to form recesses and / or through holes with an aspect ratio of 1.0 or more while suppressing tapering.

[0159] In yet another aspect, according to the present invention, it is possible to form, for example, a recess whose bottom width is 70% or more of the opening width of the recess on the initial processing surface of the workpiece, and / or a through hole whose lower opening width is 70% or more of the width of the upper opening width of the through hole on the initial processing surface of the workpiece.

[0160] Furthermore, in the present invention, since the recesses can be formed while suppressing tapering, it is also possible to form a plurality of recesses 200 and set the distance 202 between the bottoms of adjacent recesses 200 to 110% or less of the width 201 of the bottoms, as shown in Fig. 6. Therefore, in the present invention, a plurality of recesses 200 can be formed at high density.

[0161] On the other hand, in a conventional laser processing method, when multiple recesses 200′ are formed, as shown in FIG. 13, each recess 200′ is formed tapered, so that the distance 202′ between the bottoms of adjacent recesses 200′ exceeds 110% of the width 201′ of the bottom, and multiple recesses 200′ cannot be formed at a high density.

[0162] Optional aspects of the laser processing method and laser processing apparatus of the present invention will be described below, but the present invention is not limited to the specific examples described above or the modifications described below.

[0163] <Laser and Laser Light Source> The laser 1 is not particularly limited, but an excimer laser, for example, can be used. By using an excimer laser, it is possible to efficiently process a workpiece made of an organic material, such as an ABF substrate, and to achieve highly productive processing. Furthermore, because the excimer laser has low coherence, it is possible to achieve extremely uniform beam formation by using an excimer laser.

[0164] Furthermore, the use of an excimer laser allows for more precise adjustment of the processing depth and the width of the recesses and / or through holes than solid-state lasers. Excimer lasers are particularly useful for forming recesses such as fastening holes and trenches. Therefore, the use of an excimer laser allows for highly accurate processing of complex concave and convex shapes, such as circuit boards.

[0165] The irradiation shape of the laser 1 emitted from the laser light source 1 is not limited to the shapes shown in Fig. 1, Fig. 2, and Fig. 5. For example, the irradiation shape may have an intensity distribution such that the laser intensity is greatest at the center (inner side) 1a and is smaller at the skirt (outer side) 1b, as shown in Fig. 7.

[0166] <Scanning Irradiation> In the present invention, processing may be performed while the lasers 5 and 6 are scanned relatively to the surface 71 to be processed. That is, the laser processing of the present invention may be performed as scanning processing.

[0167] By performing the scan processing, it is possible to perform laser processing with high precision even on a workpiece 70 having a large area.

[0168] Furthermore, by performing the scan processing, it is possible to prevent an increase in processing time even if the number of recesses and / or through holes to be processed increases.

[0169] The scanning process can be performed by, for example, moving the workpiece 70 placed on the stage 60 and the photomask 30 in synchronization.

[0170] By doing so, laser processing can be performed without moving the lasers 1 to 6 themselves.

[0171] Furthermore, in this embodiment, the processing area is not limited to the area of ​​the lens, so an area (angle of view) larger than the area of ​​the lens can be processed.

[0172] According to this embodiment, the reduction projection optical system 50 required for irradiation can be made small, and the laser irradiation position accuracy and temperature controllability can be improved. Furthermore, since the reduction projection optical system 50, which will be described below, can be made small, image distortion due to irradiation is also reduced.

[0173] In the laser processing apparatus 100 shown in FIG. 1, the workpiece 70 placed on the stage 60 and the photomask 30 can be moved in synchronization using the controller 80.

[0174] More specifically, the controller 80 is configured to align the relative positions of the workpiece 70 and the photomask 30 based on the positional information of the characteristic parts of the photomask 30 obtained by the mask alignment camera 31 and the positional information of the characteristic parts of the workpiece 70 obtained by the workpiece alignment camera 61.

[0175] <Reduction Projection Optical System> The laser processing apparatus 100 shown in FIG. 1 is equipped with a reduction projection optical system 50, which allows the mask pattern formed on the photomask 30 to be enlarged compared to the processing pattern that is actually to be formed on the workpiece.

[0176] By enlarging the mask pattern formed on the photomask 30 more than the actual processing pattern, the energy of the laser 3 that hits the photomask 30 can be made smaller than the actual processing energy. If the reduction magnification of the reduction projection optical system 50 is N, the energy of the laser that hits the mask surface is 1 / (N ２ ) As a result, thermal drift due to the energy of the laser 3 can be suppressed, and therefore thermal expansion of the photomask 30 can be suppressed, making it possible to perform high-precision processing even after a long processing operation.

[0177] Furthermore, deterioration of optical components (for example, the optical system 20 and the photomask 30) due to the heat of the laser can be suppressed, so the life of the optical components can be extended.

[0178] The reduction projection optical system 50 can include a pair of reduction projection lenses. When the reduction projection optical system 50 is an infinity optical system, the magnification achieved by the reduction projection optical system 50 can be adjusted, for example, by adjusting the ratio of the focal lengths of the reduction projection lenses and the distance between the reduction projection lenses.

[0179] The NA of the reduction projection lens is preferably selected in accordance with the energy density and processing resolution required for processing the workpiece 70. The NA of the reduction projection lens is preferably 0.12 or greater. In the present invention, even when laser processing is performed with a high NA to form high resolution, it is possible to prevent the recesses and / or through holes formed from having a tapered shape.

[0180] The laser processing apparatus 100 of the present invention preferably further comprises a temperature adjusting means for adjusting the temperature of the reduction projection optical system 50 .

[0181] By providing a temperature control means, it is possible to further suppress the influence of heat caused by the laser energy in the reduction projection optical system 50. In the reduction projection optical system 50, the laser 4 that has passed through the photomask 30 is reduced and projected at 1 / N, so the energy of the laser that passes through the lens part at the tip of the objective is N times smaller than the energy of the laser that is irradiated onto the photomask 30. ２ Therefore, by providing the reduction projection optical system 50 with a temperature control function in order to suppress this thermal energy, it is possible to suppress the thermal drift caused by the laser energy, and it becomes possible to perform high-precision processing even after a long processing operation.

[0182] Furthermore, the laser processing method and laser processing apparatus 100 of the present invention allow the use of a reduction projection lens with a very small diameter. The temperature control means for the reduction projection lens is not directly attached to the lens itself, but rather cools the jacket portion that holds the lens. Therefore, when the lens diameter is large, while temperature control is possible around the periphery of the lens, the temperature control effect is less widespread near the crucial central portion, making heat management difficult. As a result, even a small amount of energy absorbed into the lens due to long-term laser irradiation can easily cause thermal distortion. If the laser processing apparatus 100 has a temperature control function for the reduction projection optical system 50, the lens diameter can be reduced, thereby preventing such problems.

[0183] Furthermore, it is possible to prevent defects caused by laser irradiation of the reduction projection optical system 50 and extend its life.

[0184] [Method for manufacturing substrate] The method for manufacturing a substrate of the present invention is a method for manufacturing a substrate having recesses and / or through holes, which includes forming recesses and / or through holes in a substrate, which is a workpiece, by the laser processing method of the present invention.

[0185] As described above, the laser processing method of the present invention is capable of forming a highly precise and complex pattern. Therefore, the substrate manufacturing method of the present invention, which includes the laser processing method of the present invention, makes it possible to manufacture a substrate having a highly precise and complex pattern.

[0186] [Substrate] The substrate of the present invention is a substrate used for a semiconductor package substrate. The substrate of the present invention is broadly divided into two embodiments: a first embodiment having at least two recesses, and a second embodiment having a through-hole. The substrate having at least two recesses and a through-hole may be included in both the first embodiment and the second embodiment.

[0187] Hereinafter, examples of the substrate according to the first embodiment and the substrate according to the second embodiment will be described in more detail with reference to the drawings.

[0188] <First Aspect> Fig. 14 shows a schematic partial cross-sectional view of an example of a substrate according to a first aspect of the present invention. A substrate 70 shown in Fig. 14 is a substrate used for a semiconductor package substrate.

[0189] The substrate 70 has at least two recesses 200 on its surface 71, which are adjacent to each other in a cross section 73 perpendicular to the surface 71. Each recess 200 has an opening 200A on the surface 71 of the substrate 70 and a bottom 200B. The substrate 70 has a protrusion 74 between the adjacent recesses 200. The at least two recesses 200 may have the same shape or different shapes. That is, the opening width W ａ and the width W of the bottom 200B ｂ The recesses 200 may have the same depth D ２００ (For example, the depth of the recess 200 in the thickness direction of the substrate 70) may be different for each recess 200, or may be the same processing depth D ２００ There may also be some.

[0190] The distance W between the bottoms 200B of the recesses 200 in the cross section 73 of the substrate 70 ｃ is the width W of the bottom 200B of the recess 200 ｂ The width W of the bottom 200B of the recess 200 is 110% or less, preferably 100% or more and 110% or less, and more preferably 100% or more and 105% or less. ｂ is the width W of the bottom 200B of the adjacent recess 200 ｂ The distance W between the bottoms 200B of the recesses 200 is ｃ is the shortest distance between the bottoms 200B of the recesses 200. In the substrate 70 of the first embodiment of the present invention, the distance W ｃ is the width W of the bottom 200B of the recess 200 ｂ It is sufficient to have at least two recesses 200 that are 110% or less of the above relationship, and recesses that do not satisfy this relationship may be included.

[0191] In addition, in the substrate 70, the depth D of the recess 200 in the cross section 73 ２００In the substrate 70, the width W of the bottom 200B of the recess 200 in the cross section 73 is 20 μm or less. ｂ The depth D of the recess 200 ２００ The ratio (D ２００ / W ｂ ) is 1.0 or more.

[0192] Such a substrate 70 has a distance W between the bottoms 200B of the recesses 200. ｃ is the width W of the bottom 200B of the recess 200 ｂ and the depth D of the recess 200 is 110% or less. ２００ The width W of the bottom 200B of the recess 200 is 20 μm or less. ｂ The depth D of the recess 200 ２００ The ratio (D ２００ / W ｂ ) is 1.0 or more, so the width W ｂ can be made very small. Therefore, such a substrate 70 can have a highly precise recessed pattern. Furthermore, by incorporating wiring, for example, metal wiring, into such recessed portions 200 of the substrate 70, a highly precise and complex wiring pattern can be realized.

[0193] The substrate of the first aspect can be manufactured by, for example, the laser processing method of the present invention described above or the substrate manufacturing method of the present invention, or by using the laser processing apparatus of the present invention described above.

[0194] Therefore, for example, the width W of the bottom 200B of the recess 200 ｂ can be set to 70% or more of the opening width Wa of the recess 200 on the surface 71, preferably 80% or more, and more preferably 90% or more.

[0195] In this type of substrate 70, the recess 200 is not tapered but is closer to a cylindrical shape, so that when wiring is incorporated into this recess 200, the wiring can exhibit low resistance. Therefore, substrate 70 of this type can realize a wiring pattern with low wiring resistance. Furthermore, since a large contact area can be secured at the interface between the wiring and the substrate, problems such as peeling of the wiring are less likely to occur.

[0196] Width W of the bottom 200B of the recess 200 ｂ is the opening width W ａ The ideal is to be equal to (100%).

[0197] In addition, for example, the opening width W of the recess 200 on the surface 71 ａ is preferably 20 μm or less.

[0198] With such a substrate 70, a finer wiring pattern can be realized. Although there is no particular lower limit, for example, the opening width W of the recess 200 on the surface 71 ａ can be set to 1 μm or more and 20 μm or less.

[0199] In the substrate 70 of the first embodiment, the ratio D ２００ / W ｂ The ratio D may be 1.0 or more, for example, 1.1 or more, 1.5 or more, 2.4 or more, or 3.4 or more. ２００ / W ｂ The upper limit of the ratio D ２００ / W ｂ can be set to, for example, 10.0 or less.

[0200] The opening width W of the recess 200 on the surface 71 ａ can be 20 μm or less.

[0201] Such a substrate allows for a finer wiring pattern to be realized. ａ The lower limit of the thickness is not particularly limited, but it can be set to, for example, 1 μm or more.

[0202] For example, the substrate 70 of the first embodiment has a width W ｂ is the opening width W of the recess 200 ａ 70% or more of the width W of the bottom 200B of the recess 200 ｂ The depth D of the recess 200 ２００ The substrate may have a ratio of 2.4 or more.

[0203] With such a substrate 70, it is possible to more reliably realize a highly precise, complex, and low-resistance wiring pattern.

[0204] The recess 200 may include, for example, a trench 200T as shown in the perspective view of Fig. 15. The trench 200T extends in a direction parallel to the surface 71 of the substrate 70. The multiple trenches 200T may extend in different directions from each other, as shown in Fig. 15 as an example.

[0205] The recess 200 is not limited to the trench 200T. For example, as shown in the example of Fig. 15, the recess 200 may include a fastening hole 200S having a rectangular surface shape or a fastening hole 200U having a circular surface shape. The recess 200 may also include a recess 200 having another surface shape.

[0206] Ratio D ２００ / W ｂ When the recess 200 having a width W ｂ and opening width W ａ is the width of the trench 200T in a direction perpendicular to the direction in which the trench extends. ２００ / W ｂ When the recess 200 having a value of 1.0 or more is a fastening hole 200S having a rectangular surface shape, the smallest width of the surface shape is the width W ｂ and opening width W ａ Ratio D ２００ / W ｂ When the plurality of recesses 200 having a circular surface shape are fastening holes 200U each having a diameter of the circle with a width W ｂ and opening width W ａ If the surface shape is an ellipse, the minor axis is the width W ｂ and opening width W ａ Let's say.

[0207] As described above, the substrate 70 according to the first embodiment of the present invention has a ratio D ２００ / W ｂ It is sufficient to have at least two recesses 200 in which the ratio D is 1.0 or more, and ２００ / W ｂ does not need to be 1.0 or more.

[0208] Processing depth D of recess 200 in cross section 73 ２００ (For example, the depth of the recess 200 in the thickness direction of the substrate 70) may be different for each recess 200, or may be the same processing depth D２００ The recess 200 may have a processing depth D ２００ can be set to, for example, 5 μm or more and 20 μm or less.

[0209] In a modified example, the substrate 70 of the first embodiment may have a back surface 71B opposite to the front surface 71 of the substrate 70, as shown in FIG. 16, and may further have a through-hole 300 penetrating from the front surface 71 to the back surface 71B.

[0210] Such a substrate 70 can realize a package substrate that further has a VIA electrode pattern.

[0211] For example, the width W of the upper end opening 300A of the through-hole 300 on the surface 71 ｄ is preferably 20 μm or less.

[0212] Such a substrate 70 can realize a highly precise and high-density via electrode pattern.

[0213] Width W of the upper end opening 300A ｄ The lower limit of the thickness is not particularly limited, but it can be set to, for example, 1 μm or more.

[0214] The width W of the lower end opening 300B of the through-hole 300 on the back surface 71B ｅ The processing length D of the through hole 300 ３００ The ratio can be 1.0 or greater.

[0215] Width W of the lower end opening 300B of the through hole 300 ｅ Processing length D ３００ The upper limit of the ratio is not particularly limited, but can be, for example, 1.0 or more and 10.0 or less.

[0216] Substrate 70 having such through-hole 300 can also be formed by, for example, the laser processing method of the present invention described above or the substrate manufacturing method of the present invention. Furthermore, substrate 70 can be manufactured using, for example, the laser processing apparatus of the present invention described above.

[0217] Therefore, the width W of the lower end opening 300B of the through-hole 300 on the back surface 71B ｅ is the width W of the upper end opening 300A of the through-hole 300 on the surface 71ｄ It is preferable to have such through holes 300. The substrate 70 having such through holes 300 and the at least two recesses 200 described above is a substrate of the first embodiment and a substrate of the second embodiment.

[0218] In this type of substrate 70, the through holes 300 are not tapered but are closer to a cylindrical shape, so when VIA processing is performed on these through holes 300, the VIA electrodes thus formed can exhibit low resistance. Furthermore, since a large contact area can be secured at the interface between the wiring and the substrate, problems such as peeling of the wiring are less likely to occur. Therefore, the substrate 70 of this modified example can realize a high-definition, complex, and low-resistance VIA electrode pattern.

[0219] Width W of the lower end opening 300B of the through hole 300 ｅ is the width W of the upper end opening 300A ｄ Ideally, the width W of the lower end opening 300B of the through-hole 300 should be equal to (100%). ｅ is the width W of the upper end opening 300A ｄ The ratio can be 70% or more, preferably 80% or more, and more preferably 90% or more.

[0220] For example, in the substrate 70 of the first embodiment, the width W of the lower end opening 300B of the through-hole 300 on the back surface 71B is ｅ The processing length D of the through hole 300 ３００ The ratio of is 1.0 or more, and the width W of the lower end opening 300B of the through hole 300 ｅ is the width W of the upper end opening 300A of the through-hole 300 on the surface 71 ｄ It can be 70% or more of the above, and such an embodiment is preferred.

[0221] Such a substrate 70 can reliably realize a high-definition VIA electrode pattern with reduced tapering from the front to the back. In addition, a large contact area can be secured at the interface between the wiring and the substrate, making it less likely that problems such as peeling of the wiring will occur.

[0222] Furthermore, for example, the substrate 70 of the first embodiment has a width W ｂ is the opening width W of the recess 200ａ 70% or more of the width W of the bottom 200B of the recess 200 ｂ The depth D of the recess 200 ２００ The ratio of the width W of the lower end opening 300B of the through hole 300 on the back surface 71B is 2.4 or more. ｅ The processing length D of the through hole 300 ３００ The ratio of is 1.0 or more, and the width W of the lower end opening 300B of the through hole 300 ｅ is the width W of the upper end opening 300A of the through-hole 300 on the surface 71 ｄ The substrate may be 70% or more of the above.

[0223] Such a substrate 70 can more reliably realize a high-definition VIA electrode pattern with reduced tapering from the front to the back. In addition, since a large contact area can be secured at the interface between the wiring and the substrate, problems such as peeling of the wiring are less likely to occur.

[0224] The planar shape of the through-hole 300 is not particularly limited. When the through-hole 300 has a rectangular surface shape, the smallest width of the surface shape is defined as the width W ｄ and width W ｅ When the through-hole 300 has a circular surface shape, the diameter of the circle is defined as the width W ｄ and width W ｅ If the surface shape is an ellipse, the minor axis is the width W ｄ and width W ｅ Let's say.

[0225] <Second Aspect> Fig. 17 shows a schematic partial cross-sectional view of an example of a substrate according to a second aspect of the present invention. A substrate 70 shown in Fig. 17 is a substrate used for a semiconductor package substrate.

[0226] The substrate 70 has a through-hole 300 that penetrates from the front surface 71 to the back surface 71B opposite to the front surface 71, and a width W of a lower end opening 300B of the through-hole 300 on the back surface 71B. ｅ is the width W of the upper end opening 300A of the through-hole 300 on the surface 71 ｄ This is more than 70%.

[0227] In this type of substrate 70, the through-holes 300 are not tapered but are closer to a cylindrical shape, so that when VIA processing is performed on these through-holes 300, the VIA electrodes thus formed can exhibit low resistance. Therefore, the substrate 70 of this type can realize a VIA electrode pattern with low resistance.

[0228] Furthermore, since the through-hole 300 is not tapered, the width W of the lower end opening 300B of the through-hole 300 is ｅ In order to ensure the size of the upper end opening 300A of the through hole 300, the width W ｄ Therefore, the substrate 70 of this embodiment can realize a highly precise and complicated via pattern.

[0229] Width W of the lower end opening 300B of the through hole 300 ｅ is the width W of the upper end opening 300A ｄ Ideally, the width W of the lower end opening 300B of the through-hole 300 should be equal to (100%). ｅ is the width W of the upper end opening 300A ｄ The ratio can be 70% or more, preferably 80% or more, and more preferably 90% or more.

[0230] The number of through holes 300 may be one or more. When a plurality of through holes 300 are included, the width W of the plurality of through holes 300 is ｄ and width W ｅ may be the same or different.

[0231] The planar shape of the through-hole 300 is not particularly limited. When the through-hole 300 has a rectangular surface shape, the smallest width of the surface shape is defined as the width W ｄ and width W ｅ When the through-hole 300 has a circular surface shape, the diameter of the circle is defined as the width W ｄ and width W ｅ If the surface shape is an ellipse, the minor axis is the width W ｄ and width W ｅ Let's say.

[0232] Such a substrate 70 can be formed, for example, by the laser processing method of the present invention described above or the substrate manufacturing method of the present invention. Also, the substrate 70 can be manufactured, for example, by using the laser processing apparatus of the present invention described above.

[0233] The width W of the upper end opening 300A of the through-hole 300 on the surface 71 ｄ is preferably 20 μm or less.

[0234] Such a substrate 70 makes it possible to realize a semiconductor package having a higher-definition VIA electrode pattern.

[0235] Width W of the upper end opening 300A ｄ The lower limit of the thickness is not particularly limited, but it can be set to, for example, 1 μm or more.

[0236] The width W of the lower end opening 300B of the through-hole 300 on the back surface 71B ｅ The processing length D of the through hole 300 ３００ The ratio of the width W of the lower end opening 300B of the through hole 300 can be set to, for example, 1.0 or more. ｅ Processing length D ３００ The ratio is not particularly limited, but can be, for example, 1.0 or more and 10.0 or less.

[0237] The substrate 70 of the second embodiment may further include a recess that does not penetrate from the front surface 71 to the back surface 71B. For example, the substrate 70 may include at least two recesses 200, as shown in FIG. 16, and the depth D of the recess 200 in the cross section 73 may be 1 / 2. ２００ is 20 μm or less, and the width W ｂ The depth D of the recess 200 ２００ The ratio (D ２００ / W ｂ ) may be 1.0 or more. Such a substrate 70 can also be called a substrate of the first embodiment.

[0238] As explained above, the substrate of the present invention can be formed by, for example, the laser processing method of the present invention or the substrate manufacturing method of the present invention, but it may also be manufactured by other methods. Furthermore, the substrate of the present invention can be manufactured by, for example, the laser processing apparatus of the present invention, but it may also be manufactured by other apparatus.

[0239] [Semiconductor Package Substrate] The semiconductor package substrate of the present invention is a substrate used in a semiconductor package. A semiconductor package, for example, serves to protect a semiconductor device from the external environment and provide external connection wiring terminals when the device is mounted on a printed wiring board or the like. That is, the semiconductor package substrate is a substrate used in a semiconductor package, and may or may not be equipped with a semiconductor device. Furthermore, it may or may not include a member for protecting the semiconductor device. Below, as an example, a substrate that does not include a semiconductor device and a member for protecting the semiconductor device will be described with reference to the drawings.

[0240] FIG. 18 shows a schematic partial cross-sectional view of an example of a semiconductor package substrate according to the first embodiment of the present invention.

[0241] A semiconductor package substrate 90 shown in FIG. 18 includes the substrate 70 according to the first embodiment of the present invention, which has been described with reference to FIG.

[0242] 18 has metal wiring 91 embedded in the recess 200 shown in FIG. 14. In another aspect, the semiconductor package substrate 90 can include the metal wiring 91 sandwiched between the protrusions 74 of the substrate 70.

[0243] As explained above, the presence of the recess 200 in the substrate 70 makes it possible to realize a highly precise and complex wiring pattern. Therefore, with such a semiconductor package substrate 90, it is possible to realize a semiconductor package having a highly precise and complex pattern of metal wiring 91. Furthermore, since a large contact area can be secured at the interface between the wiring and the substrate, problems such as peeling of the wiring are less likely to occur.

[0244] FIG. 19 shows a schematic partial cross-sectional view of an example of a semiconductor package substrate according to the second embodiment of the present invention.

[0245] A semiconductor package substrate 90 shown in FIG. 19 includes the substrate 70 of the example of the second aspect of the present invention shown in FIG.

[0246] 19, a via processing is performed on the through hole 300. More specifically, a via electrode 92 is formed on the surface of the substrate 70 that defines the through hole 300.

[0247] For the reasons explained above, the second embodiment of the substrate 70 can realize a high-definition via electrode pattern that is not tapered from the front surface to the back surface. Therefore, the second embodiment of the semiconductor package substrate 90 can have a high-definition via electrode pattern that is not tapered from the front surface to the back surface.

[0248] In FIG. 19, the VIA electrode 92 includes a hollow portion (through hole 300), but the VIA electrode 92 does not necessarily have to include a hollow portion.

[0249] The semiconductor package substrate 90 of the second embodiment may further include embedded metal wiring 91, as shown in Fig. 20, for example. This metal wiring 91 is embedded in the recess 200 described in the substrate of the first embodiment. Therefore, the semiconductor package substrate 90 of the example shown in Fig. 20 can also be said to be an example of the semiconductor package substrate of the first embodiment.

[0250] The sizes of the metal wirings 91 may be different from one another as shown in FIG. 20, or some may be the same.

[0251] The semiconductor package substrate 90 of the present invention may further include a surface insulating film 93, as shown in the plan view of Fig. 21. The surface insulating film 93 can cover and conceal the metal wiring 91, as indicated by the dashed lines. On the other hand, a portion of the via electrode 92 can be exposed, as shown in Fig. 21.

[0252] According to the present invention, as shown in FIG. 21, for example, a plurality of metal wirings 91 can be formed between VIA electrodes 92 in a highly precise and complicated pattern.

[0253] The substrate to be processed in the present invention may or may not be provided with circuits such as metal wiring or resist.

[0254] Furthermore, the substrate to be processed by the laser processing method of the present invention, the substrate of the present invention, and the semiconductor package substrate of the present invention may each have a rectangular planar shape, or may have another shape, for example, a circular, elliptical, or polygonal planar shape.

[0255] This specification includes the following aspects. [1] A laser processing method for forming a recess and / or a through-hole in a workpiece using a laser, wherein the laser processing method performs processing by changing the intensity distribution of the laser on the processing surface of the workpiece as an irradiation shape in which the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion. [2] The laser processing method described in [1], wherein the processing is performed by changing the shape of the intensity distribution of the laser on the processing surface of the workpiece as the processing progresses in the depth direction of the workpiece. [3] The laser processing method described in [2], wherein the processing is performed by changing the shape of the intensity distribution of the laser as the processing progresses in the depth direction of the workpiece so that the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion. [4] The laser processing method described in [3], wherein the laser has an intensity distribution in which the laser intensity is greatest at the center and smaller at the base, and the shape of the intensity distribution of the laser is changed as the processing progresses in the depth direction of the workpiece so that the intensity of the outer portion of the intensity distribution is greater than the intensity of the inner portion. [5] The laser processing method according to [4], in which a roof prism or a conical prism is used as the prism. [6] A laser processing method for forming a recess and / or a through-hole in a workpiece using a laser, the laser processing method using an optical system that shapes the laser irradiation shape into a top-hat irradiation shape, in which the intensity of the outer portion is greater than the intensity of the inner portion in the laser intensity distribution. [7] The laser processing method according to [6], in which an initial processing surface of the workpiece is processed with a laser having the top-hat irradiation shape, and at least a portion of the workpiece excluding the initial processing surface is processed with a laser having an irradiation shape in which the intensity of the outer portion is greater than the intensity of the inner portion. [8] The laser processing method according to any one of [1] to [7], in which a semiconductor package substrate is processed as the workpiece to form a recess and / or a through-hole in the semiconductor package substrate. [9] The laser processing method according to any one of [1] to [8], in which the laser is oscillated using an excimer laser oscillator.

[10] The laser processing method according to any one of [1] to [9], in which the laser is irradiated onto the workpiece via a photomask.

[11] The laser processing method according to any one of [1] to

[10] , in which processing is performed while scanning the laser relatively across the surface of the workpiece.

[12] The laser processing method according to any one of [1] to

[11] , in which ablation processing is performed.

[13] The laser processing method according to any one of [1] to

[12] , in which the recesses and / or through holes have a width of 20 μm or less.

[14] The laser processing method according to any one of [1] to

[13] , in which the recesses and / or through holes have a depth of 20 μm or less.

[15] The laser processing method according to any one of [1] to

[14] , in which the ratio of the height of the processed portion to the width of the bottom of the recess or the width of the lower opening of the through hole is 1.0 or more.

[16] The laser processing method according to any one of [1] to

[15] , wherein the recess is formed so that the width of the bottom of the recess is 70% or more of the opening width of the recess on the initial processing surface of the workpiece, and / or the through hole is formed so that the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the initial processing surface of the workpiece.

[17] The laser processing method according to any one of [1] to

[16] , wherein a plurality of the recesses are formed, and the distance between the bottoms of adjacent recesses is 110% or less of the width of the bottoms.

[18] A method for manufacturing a substrate having the recesses and / or through holes, comprising forming the recesses and / or through holes in the substrate, which is the workpiece, by the laser processing method according to any one of [1] to

[17] .

[19] A laser processing device that uses a laser to form recesses and / or through holes in a workpiece, comprising a laser light source that oscillates the laser, and an optical system that changes the irradiation shape of the laser so that the intensity distribution of the laser on the workpiece surface is such that the intensity of the outer part of the intensity distribution is greater than the intensity of the inner part.

[20] The laser processing apparatus according to

[19] , wherein the optical system includes a prism that converts a laser having an intensity distribution in which the laser intensity is greatest at the center and weaker at the base into a laser having an irradiation shape in which the intensity of the outer portion of the laser intensity distribution is greater than the intensity of the inner portion, and a shaping optical system that converts the irradiation shape of the laser converted by the prism into a top-hat irradiation shape.

[21] The laser processing apparatus according to

[20] , wherein the prism includes a roof prism or a conical prism.

[22] The laser processing apparatus according to any one of

[19] to

[21] , wherein the laser light source is an excimer laser oscillator.

[23] The laser processing apparatus according to any one of

[19] to

[22] , further including a stage on which the workpiece is placed and a photomask disposed between the optical system and the stage.

[24] The laser processing apparatus according to

[23] , further comprising a controller configured to synchronously move the workpiece placed on the stage and the photomask.

[25] A substrate used for a semiconductor package substrate, the substrate having at least two adjacent recesses on its surface in a cross section perpendicular to the surface, the distance between the bottoms of the recesses in the cross section being 110% or less of the width of the bottoms of the recesses, the depth of the recesses in the cross section being 20 μm or less, and the ratio of the depth of the recesses to the width of the bottoms of the recesses in the cross section being 1.0 or more.

[26] The substrate according to

[25] , the width of the bottoms of the recesses being 70% or more of the opening width of the recesses in the surface.

[27] The substrate according to

[26] , the opening width of the recesses in the surface being 20 μm or less.

[28] The substrate according to any one of

[25] to

[27] , wherein the ratio of the depth of the recess to the width of the bottom of the recess in the cross section is 1.1 or more.

[29] The substrate according to any one of

[25] to

[28] , wherein the ratio of the depth of the recess to the width of the bottom of the recess is 1.5 or more.

[30] The substrate according to any one of

[25] to

[29] , wherein the ratio of the depth of the recess to the width of the bottom of the recess is 2.4 or more.

[31] The substrate according to any one of

[25] to

[30] , wherein the ratio of the depth of the recess to the width of the bottom of the recess is 3.4 or more.

[32] The substrate according to

[25] , wherein the width of the bottom of the recess is 70% or more of the opening width of the recess, and wherein the ratio of the depth of the recess to the width of the bottom of the recess is 2.4 or more.

[33] The substrate according to any one of

[25] to

[32] , wherein the recess includes a trench.

[34] The substrate according to any one of

[25] to

[32] , wherein the substrate has a back surface opposite to the front surface and further has a through-hole penetrating from the front surface to the back surface.

[35] The substrate according to

[34] , wherein the width of the upper opening of the through-hole on the front surface is 20 μm or less.

[36] The substrate according to

[34] or

[35] , wherein the ratio of the processing length of the through-hole to the width of the lower opening of the through-hole on the back surface is 1.0 or more.

[37] The substrate according to any one of

[34] to

[36] , wherein the width of the lower opening of the through hole on the back surface is 70% or more of the width of the upper opening of the through hole on the front surface.

[38] The substrate according to

[34] or

[35] , wherein the ratio of the processed length of the through hole to the width of the lower opening of the through hole on the back surface is 1.0 or more, and the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the front surface.

[39] The substrate according to

[34] , wherein the width of the bottom of the recess is 70% or more of the opening width of the recess, the ratio of the depth of the recess to the width of the bottom of the recess is 2.4 or more, the ratio of the processed length of the through hole to the width of the lower opening of the through hole on the back surface is 1.0 or more, and the width of the lower opening of the through hole is 70% or more of the width of the upper opening of the through hole on the front surface.

[40] A semiconductor package substrate comprising the substrate according to any one of

[25] to

[39] , wherein metal wiring is embedded in the recess.

[41] A substrate used for a semiconductor package substrate, having a through hole penetrating from a front surface of the substrate to a back surface opposite to the front surface, and the width of a lower opening of the through hole on the back surface is 70% or more of the width of an upper opening of the through hole on the front surface.

[42] The substrate according to

[41] , wherein the width of the upper opening of the through hole on the front surface is 20 μm or less.

[43] The substrate according to

[41] or

[42] , wherein the ratio of the processed length of the through hole to the width of the lower opening of the through hole on the back surface is 1.0 or more.

[44] A semiconductor package substrate comprising the substrate according to any one of

[34] to

[39] or

[41] to

[43] , wherein the through hole is VIA processed.

[0256] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A laser processing method for forming a recess and / or a through hole in a workpiece using a laser, wherein the laser processing is performed with an irradiation shape in which the intensity of the outer portion of the intensity distribution of the laser on the processed surface of the workpiece is greater than the intensity of the inner portion.

2. The laser processing method according to claim 1, wherein as the processing proceeds in the depth direction of the workpiece, the shape of the intensity distribution of the laser on the processed surface of the workpiece is changed for processing.

3. The laser processing method according to claim 2, wherein as the processing proceeds in the depth direction of the workpiece, the shape of the intensity distribution of the laser is changed so that the intensity of the outer portion in the intensity distribution of the laser is greater than the intensity of the inner portion for processing.

4. A laser having an intensity distribution in which the central laser intensity is the largest and the skirt laser intensity is small is passed through a prism, and as the processing proceeds in the depth direction of the workpiece, the shape of the intensity distribution of the laser is changed so that the intensity of the outer portion in the intensity distribution of the laser is greater than the intensity of the inner portion for processing. The laser processing method according to claim 3.

5. The laser processing method according to claim 4, wherein as the prism, a roof prism or a conical prism is used.

6. A laser processing method for forming a recess and / or a through hole in a workpiece using a laser, wherein an optical system for shaping an irradiation shape of a laser having a shape in which the intensity of the outer portion in the intensity distribution of the laser is greater than the intensity of the inner portion into a top-hat type irradiation shape is used.

7. The initial processed surface of the workpiece is processed with a laser having the top-hat type irradiation shape, and for at least a part of the workpiece excluding the initial processed surface, processing is performed with a laser having an irradiation shape in which the intensity of the outer portion is greater than the intensity of the inner portion. The laser processing method according to claim 6.

8. The laser processing method according to any one of claims 1 to 7, wherein as the workpiece, a substrate for a semiconductor package is processed to form a recess and / or a through hole in the substrate for a semiconductor package.

9. The laser processing method according to any one of claims 1 to 7, wherein the laser is oscillated using an excimer laser oscillator.

10. The laser processing method according to any one of claims 1 to 7, wherein the laser is irradiated onto the workpiece through a photomask.

11. The laser processing method according to any one of claims 1 to 7, wherein the processing is performed while scanning the laser relative to the processed surface.

12. The laser processing method according to any one of claims 1 to 7, which performs ablation processing.

13. The laser processing method according to any one of claims 1 to 7, which forms the recess and / or the through hole having a width of 20 μm or less.

14. The laser processing method according to claim 13, which forms the recess and / or the through hole having a depth of 20 μm or less.

15. The laser processing method according to any one of claims 1 to 7, which forms the recess and / or the through hole in which the ratio of the height of the processed portion to the width of the bottom of the recess or the width of the lower end opening of the through hole is 1.0 or more.

16. Forming the recess in which the width of the bottom of the recess is 70% or more of the opening width of the recess on the initial processing surface of the workpiece, and / or The laser processing method according to any one of claims 1 to 7, which forms the through hole in which the width of the lower end opening of the through hole is 70% or more of the width of the upper end opening of the through hole on the initial processing surface of the workpiece.

17. The laser processing method according to any one of claims 1 to 7, wherein a plurality of the recesses are formed, and the distance between the bottoms of the adjacent recesses is 110% or less of the width of the bottom.

18. A method for manufacturing a substrate having the recess and / or the through hole, which includes forming the recess and / or the through hole in the substrate as the workpiece by the laser processing method according to any one of claims 1 to 7.

19. A laser processing apparatus for forming a recess and / or a through hole in a workpiece using a laser, comprising: A laser light source that oscillates the laser; An optical system that makes the irradiation shape of the laser such that the intensity distribution of the laser on the processed surface of the workpiece has an intensity of the outer portion of the intensity distribution greater than the intensity of the inner portion; A laser processing apparatus comprising the above.

20. As the optical system, A prism that converts a laser having an intensity distribution in which the central laser intensity is the largest and the skirt laser intensity is small into the laser having the irradiation shape in which the intensity of the outer portion in the intensity distribution of the laser is greater than the intensity of the inner portion; A shaping optical system that converts the irradiation shape of the laser converted by the prism into a top-hat type irradiation shape The laser processing apparatus according to claim 19, comprising the same.

21. The laser processing apparatus according to claim 20, comprising a prism including a roof prism or a conical prism.

22. The laser processing apparatus according to any one of claims 19 to 21, comprising an excimer laser oscillator as the laser light source.

23. A stage on which the workpiece is placed, A photomask disposed between the optical system and the stage The laser processing apparatus according to any one of claims 19 to 21, further comprising the same.

24. The laser processing apparatus according to claim 23, further comprising a controller configured to move the workpiece placed on the stage and the photomask synchronously.