Method for manufacturing conductor patterns
The use of short-pulse lasers to refine conductor pattern edges post-etching addresses precision and cost challenges in conductor pattern manufacturing, achieving high-precision edges with reduced thermal effects and processing time.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITUTOYO CORP
- Filing Date
- 2021-12-10
- Publication Date
- 2026-06-08
AI Technical Summary
Existing methods for manufacturing conductor patterns face challenges in achieving high precision while controlling manufacturing costs, particularly due to edge roughness and processing time issues with conventional laser and etching techniques.
A method involving the use of short-pulse lasers to refine conductor pattern edges after initial etching, minimizing thermal effects and reducing processing time by forming precise edges with minimal material scattering and edge roughness.
Enables high-precision conductor pattern edges with reduced manufacturing costs and improved throughput by shortening processing time and minimizing thermal damage.
Smart Images
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Abstract
Description
Technical Field
[0001] This case relates to Method for manufacturing conductor patterns .
Background Art
[0002] Scales for use in encoders and the like are disclosed. Scale patterns such as coils and scale gratings are formed on these scales. This scale pattern is formed by processing a conductor layer on a substrate (see, for example, Patent Documents 1 to 4).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
[0006] In one embodiment, the method for manufacturing a conductor pattern according to the present invention is characterized by comprising the steps of: preparing a substrate on which a conductor is provided on one main surface; forming the outline of a conductor pattern on the conductor using a short-pulse laser; and removing at least a portion of the area of the conductor other than the conductor pattern by etching.
[0007] In the above-described method for manufacturing the conductor pattern, a resist pattern may be formed on the conductor by photolithography, etching may be performed using the resist pattern as a mask, and then the outline of the conductor pattern may be formed by the short-pulse laser.
[0008] In the above-described method for manufacturing a conductor pattern, after forming the outline of the conductor pattern on the conductor with the short-pulse laser, a resist pattern may be formed so as to cover the conductor pattern, and then the conductor not covered by the resist pattern may be removed by etching.
[0009] The above method for manufacturing a conductor pattern includes a step of forming a plurality of conductors spaced apart from each other on a substrate, wherein after forming the outline of the conductor pattern with the short-pulse laser on the conductors, a resist pattern is formed so as to cover the conductor pattern, and thereafter, the conductors not covered by the resist pattern may be removed by etching.
[0010] Another method for manufacturing a conductor pattern according to the present invention is characterized by comprising the steps of forming a plurality of spaced-apart conductors on a substrate, and removing areas other than the conductor pattern from the conductors using a short-pulse laser.
[0011] In the above-described method for manufacturing the conductor pattern, the conductor may be formed on the substrate by printing or stamp plating.
[0012] In the above-described method for manufacturing the conductor pattern, the width of the laser-processed groove formed by the short-pulse laser may be 3 μm or more and 100 μm or less. [Effects of the Invention]
[0013] This invention provides a method for manufacturing conductor patterns that can form the edges of conductor patterns with high precision while suppressing manufacturing costs. [Brief explanation of the drawing]
[0014] [Figure 1] (a) is a plan view of the scale, and (b) is a cross-sectional view of (a) along line AA. [Figure 2] Figures (a) to (c) illustrate a method for manufacturing scale according to the first embodiment. [Figure 3] (a) to (c) are diagrams illustrating a method for manufacturing scale according to the second embodiment. [Figure 4] (a) and (b) are diagrams illustrating a method for manufacturing scale according to the third embodiment. [Figure 5] Figures (a) to (d) illustrate a method for manufacturing scale according to the fourth embodiment. [Figure 6] (a) is a plan view of the scale, and (b) is a cross-sectional view of (a) along line AA. [Modes for carrying out the invention]
[0015] (First Embodiment) FIG. 1(a) is a plan view of a scale 100 manufactured by the manufacturing method according to the first embodiment. FIG. 1(b) is a cross-sectional view taken along line A-A of FIG. 1(a). The scale 100 is, as an example, an electromagnetic induction type scale. As illustrated in FIGS. 1(a) and 1(b), the scale 100 has a structure in which a scale pattern 20 (conductor pattern) is disposed on a substrate 10. The scale pattern 20 has a structure in which a plurality of grids are arranged at a predetermined interval and constitutes a scale grid. For example, each grid of the scale pattern 20 has a length direction in a direction orthogonal to the arrangement direction of the grids on one main surface of the substrate 10. The arrangement direction of each grid is defined as the X-axis. The stacking direction of the scale pattern 20 with respect to the substrate 10 is defined as the Z-axis. The length direction of each grid, which is orthogonal to the X-axis and the Z-axis, is defined as the Y-axis.
[0016] The substrate 10 is made of, for example, prepreg (reinforced plastic molding material), polyimide, glass, CFRP (carbon fiber reinforced plastic), epoxy resin, acrylic resin, urethane resin, polyacetal resin, engineering plastic, stainless steel, invar alloy, aluminum, aluminum alloy, or the like.
[0017] The scale pattern 20 is formed of a material made of a metal conductor with low resistance such as copper, silver, or gold in the case of an electromagnetic induction type, and is formed of a metal conductor with low resistance such as copper, silver, or gold in the case of a photoelectric type, or is formed of a material made of a conductor with high reflectivity such as chromium, titanium, or titanium silicide. The width of each grid of the scale pattern 20 in the X-axis direction is, for example, 2 μm or more and 50 μm or less in the case of a photoelectric type and 500 μm or more and 3000 μm or less in the case of an electromagnetic induction type. The thickness of each grid in the Z-axis direction is, for example, 5 μm or more and 30 μm or less in order to sufficiently obtain a diamagnetic field response by high frequency.
[0018] Since the edge position of the scale pattern 20 most affects the encoder accuracy, not only the position of the edge portion but also a shape with good processing accuracy without an edge taper or edge roughness that blurs the edge position is required.
[0019] For example, in the case of a scale pattern processed by forming a resist layer on the surface of a conductive film, as described in Patent Documents 1 and 2, followed by processes such as exposure, development, and etching, there is processing variation depending on the position on the processing substrate, so the edge roughness increases with each process. In addition, in the etching process, the upper part in the film thickness direction tends to be etched the most while the lower part remains, resulting in a taper angle of 60 to 70 degrees, and the tapered region spreads unevenly to about 2 to 15 μm, hindering the improvement of processing accuracy at the edge position.
[0020] Furthermore, as shown in Patent Document 3, laser processing allows for the processing of pattern edges on thick metals in a single step, resulting in reduced edge roughness and enabling processing of irregularly shaped substrates that are difficult to mask-expose, such as long substrates. However, conventional laser processing techniques make it difficult to achieve precision processing with edge roughness of 1 μm or less due to the generation of deposits caused by material scattering during processing and deformation due to heat.
[0021] Furthermore, as described in Patent Document 4, a conductive pattern with low edge roughness can be obtained by scanning the workpiece surface with a galvanometer scanner or precision stage using a short-pulse laser such as a picosecond pulse or femtosecond pulse laser. However, in order to achieve precision, the laser spot diameter must be narrowed, and the processing area per spot becomes smaller. Therefore, processing the area excluding the conductive portion, which occupies about half the area of the substrate, requires a long processing time, and throughput does not improve. Consequently, there is a problem of increased manufacturing costs. In addition, with short-pulse lasers, even if the oscillation energy is simply increased, some of the energy is converted into heat, so the processing rate plateaus and does not increase. Therefore, throughput does not improve even if a laser oscillator with a high output is used.
[0022] Therefore, in this embodiment, we will describe a method for manufacturing scale that can form the edges of the scale pattern with high precision while suppressing manufacturing costs.
[0023] As illustrated in Figure 2(a), a substrate 10 is prepared on one main surface, with a scale pattern 20 and a conductive layer 30 made of the same material deposited by foil press molding, plating, or the like. The thickness of the conductive layer 30 is, for example, 5 μm or more and 30 μm or less. After forming a photoresist layer on this conductive layer 30, a resist pattern 40 is formed by photolithography. In this case, taking into account the amount to be formed by laser processing in a later process, the resist pattern 40 is formed so that it is slightly larger than each grid of the scale pattern 20 in the X-axis direction. For example, the excess resist pattern 40 relative to each grid of the scale pattern 20 is set to approximately 10 μm or more and 20 μm or less at both ends in the X-axis direction. The resist pattern 40 has a shape in which multiple grids are arranged at predetermined intervals, similar to the scale pattern 20.
[0024] Next, as illustrated in Figure 2(b), etching is performed using the resist pattern 40 as a mask. This partially removes the conductive layer 30, forming a pattern 30a that is substantially the same shape as the resist pattern 40. The pattern 30a, like the scale pattern 20, has a shape in which multiple grids are arranged at predetermined intervals.
[0025] Because the etching accuracy is not high, each grid portion of pattern 30a will have a roughly trapezoidal shape. For example, in each grid portion of pattern 30a, the edges at both ends in the X-axis direction will be distributed within a certain range. In this embodiment, the etching accuracy may be low. However, it is required to process with a precision that does not exceed the range of laser processing. That is, if the etching accuracy is high, the area to be removed in the next laser processing step will decrease, and thus the laser processing time can be shortened. Since the variation due to edge roughness and positional accuracy is about ±10 μm, a laser processing width of approximately 20 μm to 30 μm is required.
[0026] Next, as illustrated in Figure 2(c), after removing the resist pattern 40, a short-pulse laser is used to remove the edges of each lattice portion of pattern 30a, thereby obtaining a precise edge surface. A short-pulse laser has a pulse width on the order of femtoseconds to picoseconds and a pulse rate of 0.1 to 10 J / cm². 2 It can be defined as a laser capable of supplying pulses with a certain energy density. Short-pulse lasers can be used, for example, picosecond lasers and femtosecond lasers. By repeatedly irradiating with a short-pulse laser at a high speed of 10kHz to 5MHz, the sloped portion of pattern 30a can be removed with high precision along the Z-axis. Furthermore, because a pulse width shorter than the time it takes for light energy to be absorbed and converted into heat (approximately 1 nanosecond) is used when a short-pulse laser is used, the laser-irradiated area sublimes instantaneously without melting. This reduces thermal effects, minimizing damage such as burrs, cracks, and burns, enabling high-precision microfabrication with less damage, and thus suppressing material scattering.
[0027] According to the manufacturing method of this embodiment, the edges of each grid portion of the pattern 30a are removed by a short-pulse laser, thereby enabling the formation of high-precision edges of the scale pattern 20. For example, by setting the edge roughness to 1 μm or less, the measurement accuracy using the scale 100 can be set to 1 μm or less. Furthermore, since a short-pulse laser is used after forming a conductor pattern with low precision by etching, the processing time can be shortened compared to processing with only a short-pulse laser with a small spot diameter. This reduces manufacturing costs. As a result, it is possible to form high-precision edges of the scale pattern while suppressing manufacturing costs. In addition, the shortened processing time with the short-pulse laser reduces the effects of temperature drift. Moreover, since the etching precision does not need to be high, there is no need to use expensive high-precision lithography equipment.
[0028] (Second Embodiment) As illustrated in Figure 3(a), a substrate 10 is prepared on one main surface, with a scale pattern 20 and a conductive layer 50 made of the same material deposited on it by foil press molding, plating, or the like. The thickness of the conductive layer 50 is, for example, 5 μm or more and 30 μm or less. By partially removing the conductive layer 50 using a short-pulse laser to form laser-processed grooves, a contour with the same shape as the scale pattern 20 is formed. In this case, a pattern 50a corresponding to the scale pattern 20 and the remaining portion 50b between the patterns 50a are formed from the conductive layer 50. The spot diameter of the short-pulse laser, which allows for fine processing, is, for example, 3 μm or more and 10 μm or less. The contour should be processed with the same width as the spot diameter. Therefore, the width of the laser-processed groove can also be 3 μm or more and 10 μm or less. In order to process a homogeneous film, the laser processing conditions are consistent at all locations, and an edge pattern of uniform quality can be obtained.
[0029] Next, as illustrated in Figure 3(b), a photoresist layer is formed to cover pattern 50a and the remaining portion 50b, and then a resist pattern 60 is formed by photolithography. In this case, taking into account the amount to be shaped by laser processing in a later step, the resist pattern 60 is formed to be slightly larger than each grid of the scale pattern 20 in the X-axis direction. However, the resist pattern 60 is not left on the surface of the remaining portion 50b. For example, the end face of the resist pattern 60 is positioned near the center of the laser-processed groove in the X-axis direction.
[0030] Next, as illustrated in Figure 3(c), the remaining portion 50b is removed by etching using the resist pattern 60 as a mask. Since etching is performed with the highly accurate pattern 50a protected by the resist pattern 60, there are fewer constraints on the etching time, and etching can be easily performed without defects.
[0031] According to the manufacturing method of this embodiment, laser-processed grooves are formed in the conductive layer 50 using a short-pulse laser, allowing for the formation of a pattern 50a with high precision. For example, by setting the edge roughness to 1 μm or less, the measurement accuracy using the scale 100 can be set to 1 μm or less. Furthermore, since the remaining portion 50b is removed by etching, the processing time can be shortened compared to processing with only a short-pulse laser with a small spot diameter. This reduces manufacturing costs. As a result, the edges of the scale pattern 20 can be formed with high precision while suppressing manufacturing costs. In addition, the shortened processing time with the short-pulse laser reduces the effects of temperature drift.
[0032] Furthermore, this method minimizes the area to be laser-processed and reduces variations in processing accuracy. It also reduces the likelihood of wet etching defects. Additionally, using a permanent resist allows for the protection of precisely processed conductive pattern edges, thus reducing the number of steps involved. Consequently, productivity is higher than in the first embodiment, and it enables the processing of fine scale patterns.
[0033] (Third embodiment) As illustrated in Figure 4(a), a conductor 70 is formed on one main surface of the substrate 10 by using a conductive paste containing the same material as the scale pattern 20 as an ink, and depositing it using a printing method such as screen printing, inkjet printing, or offset printing, followed by firing, or by stamp plating. The thickness of the conductor 70 is, for example, 5 μm or more and 30 μm or less. The conductor 70 is formed so that it is slightly larger than each grid of the scale pattern 20 in the X-axis direction. The conductor 70 has a shape in which multiple grids are arranged at predetermined intervals, similar to the scale pattern 20. Because the ink spreads smoothly, each grid portion of the conductor 70 comes to have a roughly trapezoidal shape. For example, in each grid portion of the conductor 70, the edge portions at both ends in the X-axis direction come to have inclined portions that are inclined with respect to the Z-axis direction.
[0034] Next, as illustrated in Figure 4(b), a short-pulse laser is used to remove the edges of each grid portion of the conductor 70, aligning them with the end face positions of each grid in the scale pattern 20. This allows the scale pattern 20 to be obtained from the conductor 70.
[0035] According to the manufacturing method of this embodiment, the edges of each grid portion of the conductor 70 are removed by a short-pulse laser, thereby enabling the formation of the scale pattern 20 edges with high precision. For example, by setting the edge roughness to 1 μm or less, the measurement accuracy using the scale 100 can be set to 1 μm or less. Furthermore, since the conductor 70 is formed with low precision before using the short-pulse laser, the processing time can be shortened compared to processing with only a short-pulse laser with a small spot diameter. This reduces manufacturing costs. As a result, the edges of the scale pattern 20 can be formed with high precision while suppressing manufacturing costs. In addition, the shortened processing time with the short-pulse laser reduces the effects of temperature drift.
[0036] (Fourth Embodiment) As illustrated in Figure 5(a), a conductor 80 is formed on one main surface of the substrate 10 by using a conductive paste containing the same material as the scale pattern 20 as an ink, and depositing it as a film using a printing method such as screen printing, inkjet printing, or offset printing, followed by firing, or by stamp plating. The thickness of the conductor 80 is, for example, 5 μm or more and 30 μm or less. The conductor 80 is formed so that it is slightly larger than each grid of the scale pattern 20 in the X-axis direction. The conductor 80 has a shape in which multiple grids are arranged at predetermined intervals, similar to the scale pattern 20. Because the ink spreads smoothly, each grid portion of the conductor 80 comes to have a roughly trapezoidal shape. For example, in each grid portion of the conductor 80, the edge portions at both ends in the X-axis direction come to have inclined portions that are inclined with respect to the Z-axis direction.
[0037] Next, as illustrated in Figure 5(b), a short-pulse laser is used to partially remove the conductor 80 and form laser-processed grooves, thereby creating a contour with the same shape as the scale pattern 20. In this case, the scale pattern 20 and the remaining portion 80a are formed from the conductor 80. The spot diameter of the short-pulse laser, which enables fine processing, is approximately 3 μm to 10 μm. The contour should be processed with a width equal to the spot diameter. Since a homogeneous film is processed, the laser processing conditions are consistent throughout, and an edge pattern of uniform quality can be obtained.
[0038] Next, as illustrated in Figure 5(c), a photoresist layer is formed to cover the scale pattern 20 and the remaining portion 80a, and then a resist pattern 90 is formed by photolithography. In this case, taking into account the amount to be shaped by laser processing in a later step, the resist pattern 90 is formed to be slightly larger than each grid of the scale pattern 20 in the X-axis direction. However, the resist pattern 90 is not left on the surface of the remaining portion 80a. For example, the end face of the resist pattern 90 is positioned near the center of the laser-processed groove in the X-axis direction.
[0039] Next, as illustrated in Figure 5(d), the remaining portion 80a is removed by etching using the resist pattern 90 as a mask. Since etching is performed with the highly accurate scale pattern 20 protected by the resist pattern 90, there are fewer constraints on the etching time, and etching can be easily performed without defects.
[0040] According to the manufacturing method of this embodiment, laser-processed grooves are formed in the conductor 80 using a short-pulse laser, enabling the formation of scale pattern edges with high precision. For example, by setting the edge roughness to 1 μm or less, the measurement accuracy using the scale 100 can be set to 1 μm or less. Furthermore, since the remaining portion 80a is removed by etching, the processing time can be shortened compared to processing with only a short-pulse laser with a small spot diameter. This reduces manufacturing costs. As a result, it is possible to improve processing accuracy while suppressing costs. In addition, by shortening the processing time with the short-pulse laser, the effects of temperature drift can be reduced.
[0041] Furthermore, this method minimizes the area to be laser-processed and reduces variations in processing accuracy. It also reduces the likelihood of wet etching defects. Additionally, using a permanent resist allows for the protection of precisely processed conductive pattern edges, thus reducing the number of steps involved. Consequently, productivity is higher than in the first embodiment, and it enables the processing of fine scale patterns.
[0042] In the above embodiments, the scale pattern had a structure in which multiple grid shapes were arranged, but it is not limited to this. For example, the above embodiments can be applied to a scale pattern in which multiple coils are arranged at predetermined intervals in the X-axis direction.
[0043] Figure 6(a) is a plan view of a scale 100a having a scale pattern 20a in which multiple coils are arranged in the X-axis direction at predetermined intervals. Figure 6(b) is a cross-sectional view of Figure 6(a) along line AA. As illustrated in Figures 6(a) and 6(b), the scale 100a has a structure in which the scale pattern 20a is arranged on a substrate 10. The scale pattern 20a has a structure in which multiple coils are arranged at predetermined intervals. The direction of arrangement of each coil is the X-axis.
[0044] When the manufacturing method of the first embodiment is applied to scale 100a, for example, if the L&S of the coil pattern is about 1000 μm / 1000 μm, the processing will be about 50 μm wide in total across both ends of the pattern. This makes it possible to reduce the processing time to 1 / 20 compared to when the entire die-cut pattern is laser processed.
[0045] When the manufacturing method of the second embodiment is applied to scale 100a, for example, if a laser with a spot diameter of 5 μm is used, and the L&S is 1000 μm / 1000 μm, the total width at both ends will be 10 μm, thus reducing the processing time to 1 / 100.
[0046] When the manufacturing method of the third embodiment is applied to scale 100a, for example, if the L&S of the coil pattern is about 1000 μm / 1000 μm, the processing will be about 50 μm wide in total across both ends of the pattern. This makes it possible to reduce the processing time to 1 / 10 compared to when the entire die-cut pattern is laser processed.
[0047] When the manufacturing method of the fourth embodiment is applied to scale 100a, for example, if the L&S of the coil pattern is about 1000 μm / 1000 μm, the processing will be about 10 μm wide in total across both ends of the pattern. This makes it possible to reduce the processing time to 1 / 100 compared to when the entire die-cut pattern is laser processed.
[0048] Although the above embodiments are applied to electromagnetic induction scales, they may also be applied to other types of scales. For example, the above embodiments can also be applied to conductive patterns on indicators, micrometers, calipers, height gauges, linear encoders, rotary encoders, antenna patterns formed on temperature-stable glass substrates or spindle components, ultra-high-precision sensors, glass MEMS sensors, etc.
[0049] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]
[0050] 10 circuit boards 20,20a scale pattern 30 Conductor Layers 30a pattern 40 Resist Patterns 50 Conductor Layers 50a pattern 50b remaining part 60 Resist Patterns 70 Conductor 80 Conductors 80a remaining part 90 Resist Patterns 100,100a scale
Claims
1. A step of preparing a substrate on which a conductor is provided on one of the main surfaces, By irradiating the conductor with a short-pulse laser along the contour of the conductor pattern, the material is removed along the contour of the conductor pattern to a depth that exceeds the thickness of the conductor but does not penetrate the substrate. A method for manufacturing a conductor pattern, comprising the step of removing at least a portion of the region of the conductor other than the conductor pattern by etching.
2. A method for manufacturing a conductor pattern according to claim 1, characterized in that a resist pattern is formed on the conductor by photolithography, etching is performed using the resist pattern as a mask, and then the contour of the conductor pattern is formed by the short-pulse laser.
3. The method for manufacturing a conductor pattern according to claim 1, characterized in that, after forming the contour of the conductor pattern on the conductor with the short-pulse laser, a resist pattern is formed so as to cover the conductor pattern, and then the conductor not covered by the resist pattern is removed by etching.
4. The process includes forming a plurality of conductors spaced apart from each other on a substrate, The method for manufacturing a conductor pattern according to claim 1, characterized in that, after forming the contour of the conductor pattern on the conductor with the short-pulse laser, a resist pattern is formed so as to cover the conductor pattern, and then the conductor not covered by the resist pattern is removed by etching.
5. The aforementioned conductor pattern comprises a plurality of separate patterns, When removing the conductor with the short-pulse laser, the laser removes the conductor along the contours of the plurality of separate patterns to a depth that exceeds the thickness of the conductor but does not penetrate the substrate. The method for manufacturing a conductor pattern according to claim 1, characterized in that the spaces between the plurality of patterns in the conductor are removed by etching.
6. A method for manufacturing a conductor pattern according to any one of claims 1 to 5, characterized in that the width of the laser-processed groove formed by the short-pulse laser is 3 μm or more and 100 μm or less.
7. The method for manufacturing a conductor pattern according to any one of claims 1 to 6, characterized in that the short-pulse laser is a laser that is injected with a pulse width on the order of femtoseconds to picoseconds.