Surface-processed member and method for manufacturing same

Abstract

This surface-processed member is made of copper or a copper alloy and has at least a portion of the surface thereof formed by a rough surface part that is formed in a protruded-recessed shape by providing thereto a plurality of recesses C1-C8. In a 500 μm-range of a straight line E2 along the surface of a cross section of the rough surface part, the number of return parts C11-C81 which extend in one direction and in which the average value of the lengths thereof is at least 1.00 μm is 8 or more. By setting the number of return parts extending in one direction within the 500 μm-range of the straight line E2 to 8 or more, the strength of bonding with respect to a resin material covering the rough surface part can be increased, and detachment of the resin material can be prevented. The rough surface part may further be provided with a plurality of cave-in sections formed to be smaller and deeper than the recesses.

Description

Surface-treated materials and their manufacturing methods

[0001] The present invention relates to a surface-treated material and a manufacturing method thereof. This application claims priority based on Japanese Patent Application No. 2014-42160, filed on March 18, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, semiconductor components, in particular, have been required to be used in harsh environments due to the spread of autonomous driving and electric vehicles. One of the issues that has arisen in these environments is delamination. Under certain temperature ranges and vibrations, the resin material that molds semiconductor components separates from the copper material made of copper or copper alloy, which can then cause damage or lead to failure due to the intrusion of moisture, oil, etc., and semiconductor manufacturers are struggling to find a solution to this serious problem.

[0003] Techniques to prevent delamination include the use of resins that improve adhesion to copper components and roughening treatments of copper components. Roughening treatments using chemical processes such as etching and plating require the use of specialized chemical solutions, which increases costs. Furthermore, there are issues such as the need for equipment to use the chemical solutions and the difficulty of managing the chemical conditions to maintain stable quality. Furthermore, because the roughening treatment method involves immersing the product in a chemical bath, the entire material is roughened, making it difficult to meet the need to roughen only the necessary areas.

[0004] Patent Document 1 discloses that a laser is irradiated onto the surface of a copper member, and nitrides and oxides that are converted into plasma and scattered are deposited to form a dense roughened layer on the surface.

[0005] Japanese Patent Application Laid-Open No. 2022-28587

[0006] The present inventors have studied how to roughen the surface of copper members instead of depositing plasma-converted flying matter.

[0007] Therefore, an object of the present invention is to provide a surface-treated material and a method for manufacturing the same.

[0008] The present invention is a surface-treated material made of copper or a copper alloy, in which a rough surface portion is formed on at least a portion of the surface, and the rough surface portion is formed unevenly with a plurality of depressions, and the cross section of the rough surface portion has eight or more return portions extending in one direction within a linear range of 500 μm along the surface and having an average length of 1.00 μm or more.

[0009] The cross section of the rough surface portion is a cross section passing through the center or near the center of multiple depressions. One direction means either leftward or rightward as the direction in which the return portions extend when a straight line extends horizontally along the surface of the cross section of the rough surface portion. The number of return portions extending in one direction refers to the larger of the total number of return portions facing rightward and the total number of return portions facing leftward within a linear range of 500 μm. Note that if the total number of return portions facing rightward and the total number of return portions facing leftward are the same, the same number is used as the number of return portions.

[0010] The return portion has a space below it, which is further open to the outside, allowing the resin to enter through this open area. The length of the return portion is the length of an imaginary measurement line drawn in a straight line from the base to the tip of the return portion on the cross section of the rough surface portion, and is the average of the measurements of three or more locations on the return portion. The shapes of the return portion vary, with some return portions having the imaginary measurement line parallel to the 500 μm line and others having the imaginary measurement line tilted relative to the 500 μm line.

[0011] The rough surface portion has eight or more return portions extending in the same direction within a linear area of ​​500 μm on the surface in cross section, and when a resin material is laminated on the rough surface portion, it functions as an anchor.

[0012] In the surface-treated material of the present invention, the rough surface portion may further include a plurality of recessed portions that are smaller and deeper than the depressions.

[0013] By providing the rough surface portion with a plurality of recesses, the strength of the bond with the resin material (shear strength) can be increased.

[0014] The present invention is a surface-treated material made of copper or a copper alloy, in which a rough surface portion is formed on at least a portion of the surface, and the rough surface portion is formed in an uneven shape with a plurality of depressions and a plurality of recessed portions that are smaller and deeper than the depressions, and the cross section of the rough surface portion has 5 or more return portions that extend in one direction within a linear range of 500 μm along the surface and have an average length of 1.00 μm or more, and the number of the recessed portions is 4 to 20 within a field of view of 260 μm x 260 μm along the surface of the rough surface portion.

[0015] The rough surface portion has five or more return portions extending in the same direction within a linear range of 500 μm on the surface in cross section, and by providing multiple recesses, when a resin material is laminated on the rough surface portion, the strength of the bond with the resin material can be increased.

[0016] In the surface-treated material of the present invention, the average diameter of the depressions is preferably 30.00 μm or more and 100.00 μm or less. If the average diameter of the depressions is less than 30.00 μm, the length of the return portion formed will be short, and in order to improve adhesion, a high-density roughening treatment will be required. In this case, the roughening treatment of a specific area will take a long time, making it impossible to ensure productivity. On the other hand, if the average diameter of the depressions exceeds 100.00 μm, return portions will not be formed when the laser output is kept constant, and if the laser output is increased to form return portions, a strong oxide film will be formed, which is undesirable and causes a decrease in solder wettability.

[0017] In the surface-treated material of the present invention, the average depth of the depressions is preferably 0.10 μm or more and 5.00 μm or less.

[0018] If the average depth is less than 0.10 μm, the return portion will not be formed, and if the average depth is more than 5.00 μm, the laser output must be increased, and a strong oxide film will be formed, which is undesirable as it reduces solder wettability.

[0019] The surface-treated material of the present invention is preferably formed on the surface in a first direction and a second direction perpendicular to the first direction, and the pitch of the centers of the depressions in the first direction is 30 μm or more and 100 μm or less, and the pitch of the centers of the depressions in the second direction is 30 μm or more and 100 μm or less.

[0020] This allows for a suitable arrangement of multiple recesses. If the pitch between the centers of the recesses is less than 30 μm, productivity will be significantly reduced, making it impossible to ensure mass production for industrial use. Furthermore, if the pitch between the centers of the recesses is greater than 100 μm, the number of return portions formed within a 500 μm range will be less than 8, and if no recesses are provided, it will be impossible to improve adhesion.

[0021] In the surface-treated material of the present invention, adjacent recesses among the plurality of recesses may be formed such that one recess extends into a circle assumed from the periphery of the other recess.

[0022] The surface-treated material of the present invention may have a plating layer of Sn, Ni, or Ag on the surface, thereby protecting the base material made of copper or a copper alloy.

[0023] The method for producing a surface-treated material of the present invention is characterized in that a laser with an output of 10 W or more and 100 W or less is irradiated onto the surface of a substrate made of copper or a copper alloy to form a plurality of depressions.

[0024] The amount of oxides produced can be reduced by irradiating a low-power laser of 100 W or less. Also, a predetermined number of return portions that function as anchors can be formed on the periphery of the depression in the cross section.

[0025] In the method for manufacturing a surface-treated material of the present invention, preferably, where the pitch between the centers of the laser spots in the scanning direction is x2, the pitch between the centers of the laser spots in a direction perpendicular to the scanning direction is y2, the average diameter of the depressions is d, and the average depth of the depressions is h, r1 in the following equation (eq1) is set to 1.43 or less to form the depressions.

[0026]

[0027] By forming a plurality of recesses so that r1 is 1.43 or less, the return portions of these recesses can be made to function favorably as anchors.

[0028] According to the present invention, when no recesses are provided, the strength of the bond with the resin material covering the rough surface can be increased by setting the number of return portions extending in one direction within a linear range of 500 μm to 8 or more. When recesses are provided, the strength of the bond with the resin material covering the rough surface can be increased by setting the number of return portions extending in one direction within a linear range of 500 μm to 5 or more and setting the number of recesses in a predetermined field of view along the surface to 4 to 20 or less. These measures can prevent peeling of the resin material.

[0029] 7 is a diagram showing a surface-treated material according to a first embodiment of the present invention; FIG. 1 is a cross-sectional view of a depression in the surface-treated material according to FIG. 1; FIG. 2 is a cross-sectional view of a first modified example of the roughened surface portion of the surface-treated material according to FIG. 1; FIG. 3 is a cross-sectional view of a second modified example of the roughened surface portion of the surface-treated material according to FIG. 1; FIG. 4 is a cross-sectional view of the roughened surface portion according to FIG. 4; FIG. 5 is a cross-sectional view of the roughened surface portion according to FIG. 5; FIG. 6 is a cross-sectional view of the roughened surface portion according to FIG. 6; FIG. 7 is a cross-sectional view of the roughened surface portion according to FIG. 7; FIG. 8 is a cross-sectional view of the roughened surface portion according to FIG. 8; FIG. 9 is a cross-sectional view of the roughened surface portion according to FIG. 9; FIG. 10 is a cross-sectional view of the roughened surface portion according to FIG. 1;

[0030] [First Embodiment] The surface-treated material 1 shown in FIG. 1 is formed with a roughened surface portion 20, at least a portion of which is formed with a plurality of recesses 10 to form an uneven surface. The recesses 10 are aligned in a first direction D1 and a second direction D2 perpendicular to the first direction D1. Each recess 10 is formed in a substantially circular shape in a plan view, and the average diameter of the recesses 10 is preferably 30.00 μm to 100.00 μm. In the first direction D1, the recesses 10 are formed with a center-to-center pitch x1 of 30 μm to 100 μm. In the second direction D2, the recesses 10 are also formed with a center-to-center pitch y1 of 30 μm to 100 μm. FIG. 1 shows a portion of the roughened surface portion 20, and the rectangular edges of the roughened surface portion 20 are indicated by dashed two-dot lines.

[0031] The substrate of the surface-treated material 1 is made of copper or a copper alloy. Figure 2 is a cross-sectional view through the center of a depression 10 (the center of the circle). The depression 10 has a peripheral edge 11 that protrudes from the substrate surface due to the laser irradiation during manufacturing, which will be described later. In the cross-section of the depression 10 shown in Figure 2, the difference in height between the highest point of the peripheral edge 11 and the deepest point inside the peripheral edge 11 is defined as the depth h of the depression 10. The average value of the depth h is 0.10 μm or more and 5.00 μm or less. The surface-treated material 1 is formed flat, and D3 in Figure 2 is a third direction perpendicular to the first direction D1 and the second direction D2.

[0032] As shown in FIG. 2 , the peripheral edge 11 has a turned-up portion 11A extending outward from the recess 10. The turned-up portion 11A rises from the substrate surface and extends outward from the recess 10, covering a portion of the substrate surface S like an eave. A space 12 between the turned-up portion 11A and the substrate surface S is formed and opens outward from the recess 10. In the cross section of the recess 10 shown in the figure, the turned-up portion 11A of the peripheral edge 11 on the right side of the center extends upward and to the right, while the turned-up portion 11A of the peripheral edge 11 on the left side extends upward and to the left. These turned-up portions 11A have an average length L of 1.00 μm or more and 10.00 μm or less. When this surface-treated material 1 is sealed with resin, the resin fills the space 12 below the turned-up portion 11A during resin sealing, and when it solidifies, the turned-up portion 11A functions as an anchor.

[0033] The length L of the return portion 11A is determined by observing the cross section of the return portion 11A at 20,000x magnification using a scanning electron microscope. A virtual line E1 for measuring the length is drawn along the return portion 11A, extending straight from its base to its tip, as shown by the dashed line in Figure 2. The shape of the return portion 11A varies, and the virtual line E1 for measuring the length may be parallel or inclined to the 500 μm straight line E2 (described later). If the average length L of the return portion 11A is less than 1.00 μm, the rough surface portion 20 will not achieve a sufficient anchoring effect, and the laser output settings will be complicated, making it difficult to fabricate. Furthermore, if the average length L of the return portion 11A exceeds 10.00 μm, the laser output required to achieve the length L will be high, forming a strong oxide film and reducing solder wettability. The length L of the return portion is believed to be linked to the dimensions (diameter and depth) of the recess 10.

[0034] In Figure 1, the multiple depressions 10 that make up the rough surface portion 20 are aligned in a first direction D1 and also in a second direction D2, but the depressions 10 are aligned in the order in which they were formed by laser irradiation, which will be described later.If the direction in which multiple depressions 10 are formed consecutively in the same direction is hereinafter referred to as the ``scanning direction,'' then either the first direction D1 or the second direction D2 is the same as or parallel to the scanning direction, and the depressions 10 are formed side by side.

[0035] 3, the centers of the depressions 10 arranged in the even-numbered rows are displaced by Δx in the first direction D1 from the centers of the depressions 10 arranged in the odd-numbered rows. Although not shown in the figures, instead of forming the depressions 10 arranged in the even-numbered rows so as to be shifted in the first direction D1, the depressions 10 arranged in the even-numbered columns can also be formed so as to be shifted in the second direction D2.

[0036] 4, the matrix arrangement of the plurality of depressions 10 constituting the rough surface portion 20 may be such that the pitch x1 of the depressions 10 in the first direction D1 is smaller than the diameter d of the depressions 10, and in each row, one depression 10 extends into a circle that is estimated from the peripheral portion of another depression 10 adjacent to it in the first direction D1. The pitch y1 of the depressions 10 in the second direction D2 is smaller than the diameter d of the depressions 10, and in each column, one depression 10 extends into a circle that is estimated from the peripheral portion of another depression 10 adjacent to it in the second direction D2. Although not shown, either the pitch x1 in the first direction D1 or the pitch y1 in the second direction D2 may be equal to or smaller than the diameter of the depressions 10.

[0037] The recesses 10 in the rough surface portion 20 are formed by laser irradiation, which will be described later, in a line in the direction of the broken line shown in FIG.

[0038] The depressions 10 in the first and third rows are formed in order from the depression 10 on the left end to the depression 10 on the right end, and among the adjacent depressions 10 on the left and right, the depression 10 on the right side, which was formed later, extends into the circle estimated from the periphery of the depression 10 on the left side, which was formed earlier.

[0039] The depressions 10 in the second and fourth rows are formed in order from the depression 10 on the right end to the depression 10 on the left end, and among the adjacent depressions 10 on the left and right, the depression 10 on the left that was formed later extends into the circle that is assumed to be formed from the periphery of the depression 10 on the right that was formed earlier.

[0040] Here, in the arrangement of the multiple recesses 10 that make up each row, the first direction D1 is the scanning direction in the first and third rows of Figure 4, and the fourth direction D4, which is opposite to the first direction D1, is the scanning direction in the second and fourth rows.

[0041] Furthermore, in a cross section passing through the center of each depression 10 in the first row of the rough surface portion 20, the peripheral portion 11 to the left of the center of each depression 10 remains as a turned portion 11A, and each of these turned portions 11A extends in one direction, specifically in a fourth direction D4 (leftward) opposite to the scanning direction, as shown in Fig. 5. In a cross section of the depressions 10 in the third row taken along line A4-A4 in Fig. 4, each turned portion 11A extends in one direction (leftward), similar to that shown in Fig. 5.

[0042] In addition, in a cross section passing through the center of each depression 10 in the second row of the rough surface portion 20 in Fig. 4, the peripheral portion 11 to the right of the center of each depression 10 remains as a turned portion 11A, and each of these turned portions 11A extends in one direction, specifically, in a first direction D1 opposite to the scanning direction, as shown in Fig. 6. In a cross section of the multiple depressions 10 in the fourth row taken along line A5-A5 in Fig. 4, each turned portion 11A extends in one direction (to the right), similar to that shown in Fig. 6.

[0043] In the rough surface portion 20 of Figure 4, the scanning direction in which the depressions 10 are formed in order in odd-numbered rows is opposite to the scanning direction (second direction D2) in which the depressions 10 are formed in order in even-numbered rows, but these may be the same direction. In this case, the extension direction of the return portion 11A included in a cross section passing through the center of each depression 10 in the odd-numbered rows may be the same as the extension direction of the return portion 11A included in a cross section passing through the center of each depression 10 in the even-numbered rows. These directions are determined to be either rightward or leftward, even if there is a difference in inclination.

[0044] As shown in Figure 13 described below, in a cross section passing through the center of a depression 10, the peripheral portion 11 may include a turned portion 11A extending in the same direction as the turned portion of an adjacent depression 10, and may also include a turned portion 11A extending in the opposite direction.

[0045] [Number of Return Portions 11A] FIG. 7 is a diagram showing a portion of the rough surface portion 20, with the reference numerals C1 to C8 used instead of 10 to denote the depressions. The eight depressions C1 to C8, each having the same diameter, are formed with a distance between their respective peripheral edges 11, with the scanning direction being the first direction D1. In the figure, a virtual straight line E2 is shown by a dashed dotted line, passing through the centers of the eight depressions C1 to C8 and extending in the scanning direction (first direction D1) along the surface of the rough surface portion 20. The starting point P1 of the straight line E2 is set outside the leftmost depression C1, and the ending point P2 is set within the rightmost depression C8. Also in the figure, small circles indicate the locations of the peripheral edges 11 of each depression C1 to C8 that intersect with the virtual straight line E2, and these circle locations can be formed as return portions 11A.

[0046] Furthermore, in the cross section of the rough surface portion 20, if the linear distance from the start point P1 to the end point P2 of a straight line E2 along the surface is 500 μm, the number N1 of return portions 11A extending in one direction within the 500 μm linear range is set to 8 or more. Here, Figure 8 is a cross section of the rough surface portion 20 at a point passing through the centers of multiple depressions C1 to C8, and the reference numerals C11 to C82 are used for the return portions instead of 11A. "One direction" means either leftward or rightward as the direction in which the return portions extend when the straight line E2 extends horizontally as shown in Figure 8.

[0047] In the illustrated example, in each of the depressions C1 to C8, the return portions C11, C21, C31, C41, C51, C61, C71, and C81 located to the left of the center of the depression extend leftward (fourth direction D4 opposite to the scanning direction). Furthermore, each of the depressions C1 to C8 has return portions C12, C22, C32, C42, C52, C62, C72, and C82 extending rightward (in the scanning direction) at positions opposite to the left-facing return portions C11, C21, C31, C41, C51, C61, C71, and C81.

[0048] The number N1 of the return portions extending in one direction is the total number n of the return portions 11A facing leftward within a linear range of 500 μm. １１ and the total number n of right-facing return portions 11A １２ The total number of left-facing numbers n is specified. １１ and the total number of right-facing １２ In the example of the configuration shown in FIG. 8, the total number n of the left-facing turned portions 11A is set to N1. １１ is 8 (C11, C21, C31, C41, C51, C61, C71, C81), and the total number n of the right-facing turned-back portions 11A is １２ Since the number of return portions N1 is 8 (C12, C22, C32, C42, C52, C62, C72), the number of return portions N1 is 8.

[0049] When specifying the number N1 of the return portions 11A, the cross section of the rough surface portion is not limited to a cross section passing through the center of each recess, but may be a cross section passing through the vicinity of each center of a plurality of recesses, and in this case, the straight line E2 is also assumed to extend in the scanning direction. １１ and the total number of right-facing １２ It is possible to identify the following.

[0050] By having eight return portions C11, C21, C31, C41, C51, C61, C71, and C81 within 500 μm, the resin material covering the rough surface portion 20 can be suitably held. If the number N1 of return portions 11A extending in one direction within 500 μm is less than 8, there is a risk that the resin material covering the rough surface portion 20 will peel off. Note that, by shortening the pitch x1 between the centers of the depressions 10 as shown in FIG. 4, the number of return portions 11A extending in the same direction within 500 μm can be made 9 or more.

[0051] [Method for manufacturing surface-treated material 1] As shown in the flowchart of Figure 9, the method for manufacturing surface-treated material 1 includes a roughening step in which the surface of a plate-shaped substrate made of copper or a copper alloy and having a thickness of 0.1 mm to 10 mm is roughened, a pressing step in which the substrate that has undergone the roughening step is pressed to cut out a final material having a desired pattern, and a cleaning step in which the final processed material is cleaned.

[0052] In the roughening step, the surface of the substrate is processed using a laser irradiation device. The laser output of the laser irradiation device is set to 10 W or more, preferably a low output of 100 W or less, more preferably 90 W or less, for example, 20 W or 25 W. If the output is less than 10 W, depressions cannot be formed and improved adhesion cannot be achieved, while if the output is more than 100 W, the high output will result in the formation of a strong oxide film, which will reduce solder wettability, and is therefore undesirable.

[0053] The pulse frequency is 10 kHz or more and 100 kHz or less, and the scan speed is 10,000 mm / s or more. The laser irradiation of the surface of the substrate is performed with a pitch x2 in the scanning direction of 30 μm or more and 100 μm or less, processing one column or row, and a pitch y2 at which the laser spot position is displaced in a direction perpendicular to the scanning direction after one column or row is completed is 30 μm or more and 100 μm or less. The scanning direction may be the same across the entire area to be processed, or, for example, the scanning direction may be reversed for each row. The laser irradiation of the substrate is performed in an oxygen-containing atmosphere.

[0054] [Ratio r1] The ratio r1 of the area that can be filled by one depression 10 to an area having the size of the product of the pitches x2 and y2 of the laser irradiation conditions is expressed by the following formula (1). In the roughening process, the rough surface portion 20 is formed so as to satisfy the condition that the ratio r1 is 1.43 or less. By setting the ratio r1 to 1.43 or less, it is possible to maintain a state in which the resin material is firmly bonded.

[0055]

[0056] In the pressing process, the material is processed into a desired shape, and then goes through a cleaning process to form the surface-treated material 1, which is then used to complete, for example, a lead frame. The cleaning process preferably includes a step of removing oxides formed on the surface by acid cleaning.

[0057] As shown in Fig. 10, the manufacturing method of the surface-treated material 1 may include a plating step of forming a plating layer on the surface of the substrate before the roughening step. This plating layer contains Sn, Ni, or Ag, and is formed, for example, in a location away from the roughened surface. The plating layer formed in the plating step may also be subjected to a roughening step.

[0058] The manufacturing method of the surface-treated material 1 may also include a post-plating anti-rust treatment step in which, after the roughening step and the cleaning step, a plating layer is provided on the surface of the base material as an anti-rust treatment. This plating layer contains any of Cu, Sn, Ni, and Ag, and is applied to the outer lead portion that is exposed to the outside and separate from the roughened surface portion that is sealed with resin, for example.

[0059] 10, the plating step and the roughening step may be reversed, and the plating step may be performed after the roughening step. In this case, the rough surface portion is covered with a plated layer by the plating step.

[0060] Furthermore, the pressing step may be divided into two or more steps, for example, a step of processing the inner shape of the surface-treated material and a step of processing the outer shape. In this case, the first pressing step and the second pressing step may be performed consecutively, or may be performed with another step (e.g., a roughening step) sandwiched between them.

[0061] The surface-treated material 1 can be used with at least the portion including the rough surface portion 20 molded with resin.

[0062] In the surface-treated material 1, by setting the number N1 of the return portions 11A of the rough surface portion 20 extending in the same direction within a linear range of 500 μm in the cross section to 8 or more, the resin material can be held in place and peeling or cracking of the resin material can be prevented.

[0063] In Patent Document 1, a high-power laser of 6000 W is irradiated to form a dense roughened layer on the surface by solidifying the melted material and depositing oxides that are converted into plasma by the laser and scattered, improving resin adhesion, but there is a risk of reducing solder wettability. On the other hand, in the present invention, the amount of oxide generated can be reduced by forming depressions by irradiating a low-power laser of 100 W or less.

[0064] [Second embodiment] In the surface-treated material 2 of the second embodiment, as shown in Figure 11, the rough surface portion 30 is composed of a plurality of depressions 10 and recessed portions 40 that are formed deeper and have a smaller planar size than the diameter d of these depressions 10.

[0065] The recessed portion 40 is formed in a polygonal shape such as a triangle or a square, or a circle in plan view, and the average depth thereof is 1.00 μm or more and 100.00 μm or less, with the flat portion 50 around the depression 10 being taken as the reference plane.

[0066] The pitch a between the centers of the recesses 40 in the first direction D1 is 50 μm or more and 500 μm or less, and the pitch b between the centers of the recesses 40 in the second direction D2 is 50 μm or more and 500 μm or less. These pitches a and b are set larger than the pitches x1 and y1 of the depressions 10.

[0067] The recessed portions 40 can be formed by forming a plurality of recesses 10 in the base material by laser irradiation, and then using a punch provided with a plurality of protrusions to recess the recesses 10 and / or the flat portions 50. The reverse may also be true, and the recessed portions 40 may be formed first and then the recesses 10 may be formed.

[0068] The plurality of recesses 40 are formed by pressing, and the rough surface portion 30 can be formed by controlling the number of recesses 40 .

[0069] The number N2 of recesses 40 is 4 or more and 20 or less within a field of view of 260 μm×260 μm along the surface.

[0070] In the rough surface portion 30, by providing a plurality of recesses 40, the number of return portions 11A in the same direction included in a 500 μm area of ​​the cross section can be reduced, and the number N of return portions 11A may be 5 or more.

[0071] In the surface-treated material 2, the number N of return portions 11A extending in the same direction within a linear range of 500 μm along the cross section of the rough surface portion 30 is set to 5 or more, and the recessed portion 40 is further provided, thereby making it possible to hold the resin material in a suitable manner, thereby preventing peeling and cracking of the resin material.

[0072] When forming the surface-treated material 2 of this second embodiment, the roughening process is divided into a process of forming depressions 10 by laser irradiation and a process of forming recesses 40 by punching. For example, as shown in the flowchart of FIG. 12, a press roughening process of forming recesses 40 by pressing can be performed before the laser roughening process of forming depressions 10 by laser. The laser roughening process and the press roughening process can be performed in reverse, and these two processes do not need to be consecutive; other processes can be interposed between the two processes. Pressing for processing the outer shape of the surface-treated material can be performed during the press roughening process. Furthermore, although the flowchart of FIG. 12 shows a cleaning process following the laser roughening process, a rust prevention treatment process can also be interposed.

[0073] The present invention can be practiced without being limited to the above-described and illustrated examples.

[0074] The recessed portion 40 may be formed in the rough surface portion 20 of the first embodiment.

[0075] In the illustrated example, the rough surface portion is formed on one side of the surface-treated material, but the rough surface portion may be formed on both sides of the surface-treated material.

[0076] The surface-treated material may also be formed with a plurality of roughened portions distributed on one surface.

[0077] Samples 1 to 8, 10, 17, and 18 were prepared by changing the laser irradiation conditions on the surface of a copper alloy substrate to form a rough surface portion consisting of a plurality of depressions. A resin material was solidified on the rough surface portion of each of Samples 1 to 8, 10, 17, and 18 to form protrusions, and a load was applied to these protrusions to confirm the shear strength at which the protrusions peeled off from the rough surface portion.

[0078] [Laser Irradiation Conditions] The laser output was either 20 W or 25 W. The scanning speed, which is the speed at which the laser irradiation location is displaced in the scanning direction, was 1500 mm / s or more and 10000 mm / s or less. The pulse frequency was either 30 kHz or 50 kHz.

[0079] The pitch x2 is the distance between the centers of the laser irradiation spots in the scanning direction, and the pitch x2 is set to 30 μm or more and 333 μm or less.

[0080] A row of dimples is formed by irradiating the laser in the scanning direction for a predetermined distance. The rough surface portion has a plurality of rows of dimples, and the pitch y2 between these rows is defined as the fill interval, and is set to be 30 μm or more and 333 μm or less.

[0081] The laser irradiation conditions for forming the roughened surface of each of Samples 1 to 8, 10, 17, and 18, including laser output, scan speed, pulse frequency, and pitches x2 and y2, are shown in Table 1. Note that none of the samples underwent press processing to form recesses smaller and deeper than the depressions formed by laser irradiation. For each sample, three plate pieces were cut out from the plate material that had been subjected to laser roughening treatment; one was used to measure the dimensions of the depressions in the roughened surface, one was used for a shear test, and the remaining one was used for a solder wettability test.

[0082] [Measurement of Diameter d of Indentations] The rough surface of the sample was observed at 50x magnification using a laser microscope. Three locations on the arc-shaped periphery of one indentation in the field of view were designated. The center of the indentation was identified and its diameter was determined using the three-point circle method. An OLIMPUS LEXT laser microscope was used. Specifically, when three or more indentations were included in one observation field, only one observation location was used, and the diameter d of each indentation within the observation field was determined. The average of these diameters d was used as the measured value. Alternatively, when the number of indentations included in one observation field was less than three, multiple observation locations were used so that the total number of indentations required to determine the diameter d was three or more. The diameter d of each indentation within each observation field was determined, and the average of these diameters d was used as the measured value. The measured values ​​of diameter d for Samples 1 to 8, 10, 17, and 18 are shown in Table 1.

[0083] [Measurement of Depth h of Indentations] A cross-sectional profile of the rough surface was created using a laser microscope, and the depth h from the maximum height to the deepest part of one indentation was determined from this profile. This depth was determined for each of three indentations, and the average value was used as the measured depth h. The measured depth h values ​​for each of Samples 1 to 8, 10, 17, and 18 are shown in Table 1.

[0084] [Measurement of the number of return portions N1] A plurality of depressions aligned in the scanning direction on the rough surface portion were cut along a straight line passing through each center or their vicinity, and the number of return portions N1 within a linear range of 500 μm along the surface of the cross section was determined. １１ and the total number of right-facing １２ The total number of left-facing turns n is calculated as follows: １１ and the total number of right-facing １２ and 17 were the same, the same number was taken as the number of return portions N1. The length of each return portion must be 1.00 μm or more as measured by the measurement method described below. A scanning electron microscope was used as the measuring device. Three linear ranges of 500 μm were observed to determine the number N1 for each, and the smallest number among these was taken as the measured value. The measured values ​​of the number N1 of return portions for each of Samples 1 to 8, 10, 17, and 18 are shown in Table 1.

[0085] [Measurement of the Length L of the Turned Portion] The length of the turned portion was determined by observing the peripheral portion of a cross section passing through the center of the depression at 100,000x magnification using a scanning electron microscope. A virtual line E1 for measuring the length of the turned portion was drawn from its base to its tip. The turned portion must have an open space below it. For example, the cross section of the peripheral portion shown in Figure 13 has a turned portion extending to the left and a turned portion extending to the right. The virtual line E1 for measuring the length of each turned portion is represented by a dashed dotted line. The length L11 of the left turned portion is 2.20 μm, and the length L12 of the right turned portion is 1.62 μm. For each of Samples 1 to 8, 10, 17, and 18, three fields of view were observed, and the lengths of the right-facing turned portions were measured. The average of these measurements was used as the measurement value for the right-facing turned portion. Similarly, the measurement values ​​for the left-facing turned portions were determined. The larger of the measured value of the right-facing turned portion and the measured value of the left-facing turned portion was taken as the measured length of the turned portion L. The measured values ​​L for each of Samples 1 to 8, 10, 17, and 18 are shown in Table 1.

[0086] [Ratio r1] The measured diameter d and depth h of the dents, and the pitches x2 and y2 of the laser irradiation conditions were substituted into the above formula (1) to determine the ratio r1. This ratio r1 is calculated by multiplying the area (= x2 × y2) formed by the product of the pitches of the laser irradiation conditions by the surface area of ​​the dents (= π × (h ２ +(d / 2) ２ The ratio r1 for each of Samples 1 to 8, 10, 17 and 18 is shown in Table 1.

[0087] [Shear Test] In the shear test, resin projections were formed on the rough surface of the sample, a jig was pressed against the projections fixed to the rough surface, and the maximum load at which the projections peeled off from the rough surface was measured.

[0088] As shown in Figure 14, samples 1 to 8, 10, 17, and 18 (denoted by the reference numeral 100 in Figure 14 and hereinafter sometimes referred to as sample 100) have dimensions of 0.50 mm in thickness, 10.00 mm in length, and 40.00 mm in width. The dimensions of protrusion 200 are an upper surface diameter of 3.00 mm, a lower surface diameter of 3.57 mm, and a height of 4.00 mm, and the side surface 210 extending from the periphery of the upper surface to the periphery of the lower surface is tapered. Four of these protrusions 200 are formed at longitudinally intermediate positions on the rough surface of sample 100, spaced apart from one another.

[0089] The properties of the resin molded on the sample are as follows: Glass transition temperature: 200°C Linear expansion coefficient (α1): 15 ppm / °C Linear expansion coefficient (α2): 55 ppm / °C Hot hardness: -85 Flexural modulus: 13 GPa Flexural strength: 100 MPa

[0090] The testing machine used was a DAGE manufactured by Nordson. A jig 300 for applying a load to the protrusions 200 was brought into contact with the side surfaces 210 of the four protrusions 200, and then the jig 300 was moved horizontally at a speed of 50 μm / s to apply a load to the four protrusions 200. The measurement load range was set to 50 kg. The jig 300 was also brought into contact with the side surfaces 210 at a height of 0.10 mm from the surface of the sample 100.

[0091] In the shear test, the sample 100 provided with the protrusions 200 was set in a testing machine heated to 250°C (actual measurement), and then this state was maintained for 5 minutes as preheating, after which the jig 300 was moved to measure the peak strength when the protrusions 200 peeled off the sample 100, and this measured value was taken as the shear strength m1. The shear test was also performed on sample 9, which had not been subjected to the roughening process.

[0092] Of the obtained measured values, the shear strength of sample 9, which was not subjected to the roughening process, was taken as a reference value m1 ｒｅｆ As shown in the following formula (2), the reference value m1 ｒｅｆ The shear strength improvement rate r2 [%] of each of Samples 1 to 8, 10, 17 and 18 was calculated from the ratio of the shear strength m1 of each sample to the shear strength m2 of each sample.

[0093]

[0094] In the shear test, a shear strength improvement rate r2 of 50% or more was evaluated as good, and a rate of less than 50% was evaluated as poor. The evaluation results of the shear test for each of Samples 1 to 8, 10, 17, and 18 are shown in Table 1.

[0095] [Solder wettability test] The test method was a dip test using eutectic solder at 240°C or higher for 5 seconds or more. A sample with a rough surface that was wetted with solder of 90% or more was rated as good, and a sample with a wetted area of ​​less than 90% was rated as bad. The evaluation of the solder wettability test for each of Samples 1 to 10, 17, and 18 is shown in Table 1.

[0096]

[0097] In samples 1 to 4, 7, 10, and 18, the number of return portions N1 within a 500 μm linear range along the surface in the cross section of the rough surface was 8 or more, which enabled the improvement rate r2 of shear strength to be 50% or more. Figure 15 is a photograph of the rough surface of sample 4. The depressions, which are approximately circular in plan view, are formed in rows so that they partially overlap with adjacent depressions. Samples 1 to 4, 7, and 18 also had good solder wettability. Sample 10 had a laser output of over 100 W, and its solder wettability was poor.

[0098] In samples 5, 6, 8, and 17, the number of return portions N1 within a 500 μm linear range along the surface in the cross section of the rough surface was less than 8, resulting in a shear strength improvement rate r2 of less than 50%. In addition, samples 5, 6, 8, and 17 had good solder wettability. Figure 16 is a photograph of the rough surface of sample 5. In this case, the scanning speed was fast, so the depressions, which are approximately circular in plan view, are formed at intervals without overlapping. In sample 17, eight raised areas were observed on the periphery of each depression within a 500 μm range of the cross section of the rough surface. However, these did not extend in either the scanning direction or the opposite direction, and none of them could be identified as return portions.

[0099] Samples 11 to 15 were substrates made of a copper alloy and having a rough surface portion consisting of a plurality of depressions and recessed portions formed by pressing. As in Example 1, a resin material was solidified on the rough surface portion of each of Samples 11 to 15 to form protrusions, and a weight was applied to these protrusions to confirm the shear strength at which the protrusions peeled off from the rough surface portion.

[0100] The laser irradiation conditions are in the same range as in Example 1.

[0101] [Recessed portion] A plurality of recessed portions were formed by pressing in the uneven portion consisting of a plurality of depressions. The recessed portions were arranged at a pitch a of 90 μm in the direction parallel to the laser scanning direction and at a pitch b of 90 μm in the direction intersecting the scanning direction.

[0102] The number of recesses 40 was determined by observing a 260 μm × 260 μm field of view of the rough surface of the sample using a laser microscope. The number of recesses 40 was determined in each of the observation fields at multiple locations, and the maximum value among these was used as the measured value. In addition to the samples used for the shear test, the number of recesses 40 was determined using samples prepared under the same conditions. The number of recesses 40 for each sample is shown in Table 2.

[0103] In Example 2, the diameter d of the recess, the depth h of the recess, the number N1 of the return portions, the length L of the return portions, the calculation of the ratio r1, the shear test, and the solder wettability test were performed under the same conditions as in Example 1. These measured values ​​and the evaluation of each test are shown in Table 2. A shear test was also performed on Sample 16, which did not have multiple recesses but had recessed portions at the above pitch.

[0104]

[0105] In samples 11 to 13, the number of return portions N1 within a 500 μm linear range along the surface in the cross section of the roughened surface was 5 or more, and the number of recessed portions N2 within a 260 μm × 260 μm field of view along the surface of the roughened surface was 9, so the improvement rate r2 of shear strength was 50% or more. Samples 11 to 13 also had good solder wettability.

[0106] In samples 14 and 15, recesses were provided, but the improvement rate r2 of shear strength was less than 50% because the number N1 of return portions within a 500 μm linear range along the surface in the cross section of the rough surface was less than 5. Samples 14 and 15 had good solder wettability.

[0107] Sample 16 has a plurality of recessed portions without a plurality of depressions, but it was confirmed that it is difficult to improve the shear strength with only a plurality of recessed portions.

[0108] The surface-treated material of the present invention can be used for lead frames that are mounted with semiconductor components and sealed with resin.

[0109] 1, 2 Surface-treated material 10 Depression C1 to C8 Depression 11 Peripheral edge 11A Turned portion C11 to C82 Turned portion 12 Space portion 20, 30 Rough surface portion 40 Recessed portion E2 Straight line

Claims

1. A surface-treated material made of copper or a copper alloy, wherein a roughened surface is formed on at least a portion of the surface, and the roughened surface is formed into an uneven shape by a plurality of depressions, and the cross section of the roughened surface has 8 or more return portions extending in one direction within a linear range of 500 μm along the surface, with an average length of 1.00 μm or more.

2. The surface-treated material according to claim 1, wherein the rough surface portion further comprises a plurality of recesses formed smaller and deeper than the depressions.

3. A surface-treated material made of copper or a copper alloy, wherein a rough surface portion is formed on at least a portion of the surface, and the rough surface portion is formed in an uneven pattern with a plurality of depressions and a plurality of recessed portions that are smaller and deeper than the depressions, and the cross section of the rough surface portion has 5 or more return portions that extend in one direction within a linear range of 500 μm along the surface and have an average length of 1.00 μm or more, and the number of recessed portions is 4 to 20 within a field of view of 260 μm x 260 μm along the surface of the rough surface portion.

4. A surface-treated material according to any one of claims 1 to 3, characterized in that the average depth of the depressions is 0.10 μm or more and 5.00 μm or less.

5. A surface-treated material according to any one of claims 1 to 3, characterized in that the depressions are formed on the surface in a first direction and in a second direction perpendicular to the first direction, the central pitch in the first direction being 30 μm or more and 100 μm or less, and the central pitch in the second direction being 30 μm or more and 100 μm or less.

6. A surface-treated material as described in any one of claims 1 to 3, characterized in that, among the plurality of recesses, adjacent recesses are formed such that one extends into a circle assumed to extend from the peripheral edge of the other.

7. A surface-treated material according to any one of claims 1 to 3, characterized in that the surface has a plating layer of any of Sn, Ni, and Ag.

8. A method for manufacturing a surface-treated material, characterized by forming a plurality of depressions by irradiating a laser having an output of 10 W or more and 100 W or less onto the surface of a substrate made of copper or a copper alloy.

9. A method for manufacturing a surface-treated material as described in claim 8, characterized in that, when the pitch between the centers of the laser spots in the scanning direction is x2, the pitch between the centers of the laser spots in a direction perpendicular to the scanning direction is y2, the average diameter of the depressions is d, and the average depth of the depressions is h, r1 in the following equation (eq1) is set to 1.43 or less to form a plurality of depressions.

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