TW201830627A - Lead frame member and method for manufacturing same, and semiconductor package - Google Patents

Abstract

A lead frame member (10) is provided with an electrically conductive substrate (1) and a roughened film (3) which includes at least one roughened layer (2) formed of a plurality of roughened particle projections (4) on at least one side of the electrically conductive substrate (1), either directly or with an intermediate layer interposed therebetween. The projections (4) have a shape such that a maximum width measured at a thickness-direction cross section of the roughened film (3) is 1 to 5 times a minimum width measured at a lower portion positioned on the electrically conductive substrate (1) side below the position at which the maximum width is measured.

Description

   Lead frame material, manufacturing method thereof, and semiconductor package   

The present invention relates to a lead frame material, a method for manufacturing the same, and a semiconductor package. The semiconductor element and the lead frame having a surface treatment layer are electrically connected to each other. .

Such a resin-sealed semiconductor device has a structure in which a semiconductor element and a lead frame electrically connected to each other by a lead or the like are sealed with a cast resin. Such a resin-sealed semiconductor device is generally manufactured by subjecting a lead frame to surface treatment such as exterior plating, for example, forming a surface film with an Sn alloy such as an Sn-Pb alloy or an Sn-Bi alloy.

Here, in recent years, in order to simplify the assembly steps and reduce costs, plating on the surface of the lead frame in advance has been performed in accordance with specifications such as soldering of printed circuit boards to improve solder wettability and other specifications ( For example, a lead frame (Pre-Plated Frame) of Ni / Pd / Au (for example, refer to Patent Document 1).

On the other hand, in order to improve the adhesion between the lead frame of the resin-sealed semiconductor device and the cast resin, a technique for roughening the plating surface of the lead frame has been proposed (for example, refer to Patent Document 2).

The technology of roughening the plating surface is to roughen the lead frame by roughening the surface of the lead frame. It is expected that (1) the casting resin will enter the unevenness of the roughened plating film and form a strong mechanical joint. Effect (anchoring effect), (2) chemical bonding by improving the contact area between the casting resin and the plating surface.

By roughening the surface of the lead frame, improving the adhesion of the cast resin to the lead frame, and suppressing the peeling between the lead frame and the cast resin, the reliability of the resin-sealed semiconductor device can be improved.

[Prior technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 4-115558

[Patent Document 2] Japanese Patent Laid-Open No. 6-029439

By roughening the surface of the lead frame, it is possible to improve the adhesion of the cast resin to the lead frame compared to the previous resin-sealed semiconductor devices. However, in recent years, the requirements for reliability have become stricter than before, and high-temperature and high-humidity durability tests are required. For example, even in an environment with a temperature of 85 ° C and a humidity of 85%, it is severe for 168 hours. When the high temperature and high humidity test is performed under the conditions, the reliability standard must be passed. On the other hand, as in Patent Document 1, a conventional structure that only roughens the surface of the lead frame may cause a gap between the resin and the lead frame, and fail to pass the reliability standard. This is considered to be due to the recent use of packages such as QFN (Quad Flat Non-Leaded Package) and SOP (Small Outline Package) types as resin-sealed semiconductor devices. Requirement to become higher. As described above, in the resin-sealed semiconductor device, the adhesion to the lead frame resin is required to maintain good adhesion even under the severe conditions described above, and further improvement is required.

An object of the present invention is to provide a suitable lead frame material, a method for manufacturing the same, and a semiconductor package having high reliability, and the formation thereof can be maintained well even when a high-temperature and high-humidity test is performed particularly under the severe conditions described above. Resin-adhesive leadframe surface.

The present inventors conducted intensive research in order to solve the above-mentioned problems, and considered that the cross-sectional shape of the roughened particle protrusions constituting the roughened layer of the roughened film formed on the conductive substrate may greatly affect the resin adhesion, and investigated Whether the good adhesion caused by the so-called anchoring effect generated by the resin filling on the uneven surface (especially the concave portion) of the protrusion formed by the surface of the lead frame material is under the severe conditions described above It can also be maintained during the high temperature and high humidity test.

Then, the present inventors obtained the following insight: by controlling the protrusions of the roughened layer of the roughened film formed on the conductive substrate, the protrusions are controlled to have a maximum width when measured in a thickness direction cross section of the roughened film. The width is 1 to 5 times the smallest width when measured at the lower part of the conductive substrate than the measurement position of the maximum width, especially for the protrusions of roughened particles. At the smallest width, it is possible to effectively suppress the peeling of the resin easily due to stress concentration such as expansion or contraction of the resin. As a result, it was found that the good adhesion due to the anchoring effect can be maximized by the roughened layer, and by controlling the protrusions forming the roughened layer to the above-mentioned shape, even if the high temperature and the high temperature that were previously unbearable were increased, The wet durability test, for example, can also maintain good resin adhesion to the lead frame when the high-temperature and high-humidity test is performed under the severe conditions of 168 hours in an environment with a temperature of 85 ° C and a humidity of 85%.

That is, the main points of the present invention are as follows.

(1) A lead frame material comprising: a conductive substrate; and a roughened film formed on at least one side of the conductive substrate, directly or via an intermediate layer, formed by a plurality of roughened particle protrusions. At least one roughened layer, the protrusion has a maximum width when measured in a cross-section of the thickness direction of the roughened film, and is located closer to the conductive substrate than the measurement position of the maximum width. The minimum width when measured at the lower part is 1 to 5 times.

(2) The lead frame material according to the above (1), wherein the conductive base system is copper, copper alloy, iron, iron alloy, aluminum, or aluminum alloy.

(3) The lead frame material according to the above (1) or (2), wherein the roughened layer comprises a material selected from the group consisting of copper, copper alloy, nickel, nickel alloy, palladium, palladium alloy, silver, silver alloy, tin, A metal or alloy of the group consisting of tin alloy, zinc, zinc alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, iridium and iridium alloy.

(4) The lead frame material according to any one of (1) to (3) above, further comprising a surface film including at least one surface coating layer on at least a part of a surface of the roughened film, The surface coating layer includes a metal selected from the group consisting of palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver, and silver alloy. Or alloy.

(5) The lead frame material according to the above (4), wherein the intermediate layer is nickel, a nickel alloy, cobalt, a cobalt alloy, copper, or a copper alloy.

(6) A method for manufacturing a lead frame material, comprising the step of forming a roughened film, the roughened film being included on at least one side of the conductive substrate, directly or via an intermediate layer, and a plurality of roughenings by electroplating. At least one roughened layer formed by the protrusions of the particles, and the protrusions have a maximum width when measured by a cross section in the thickness direction of the roughened film, and are located at a position relatively larger than a measurement position of the maximum width. The minimum width when measured on the lower portion of the conductive substrate is 1 to 5 times.

(7) A semiconductor package comprising the lead frame material according to any one of (1) to (5) above.

The lead frame material of the present invention includes: a conductive substrate; and a roughened film including at least one layer formed on a surface of the conductive substrate, directly or via an intermediate layer, with a plurality of roughened particle protrusions. The roughened layer, wherein the protrusion has a maximum width when measured in a cross-section of the thickness direction of the roughened film, and is located at a lower side of the conductive substrate than the measurement position of the maximum width. The minimum width during measurement is 1 to 5 times. Based on the above, even if a high temperature and high humidity durability test is performed, for example, a high temperature and high humidity test is performed under the severe conditions of 168 hours in an environment with a temperature of 85 ° C and a humidity of 85%, a good resin density for the lead frame can be maintained. The semiconductor package is made of the lead frame material, and the reliability is hardly deteriorated.

1‧‧‧ conductive substrate

2‧‧‧ coarsening layer

2-1‧‧‧The first roughened layer (the first roughened layer from the substrate side)

2-2‧‧‧ 2nd roughened layer (2nd roughened layer from the substrate side)

3.3-1‧‧‧roughened film

4, 4-1‧‧‧ protrusion

10, 10A‧‧‧ lead frame material

A‧‧‧ The length of the section line of the outermost surface of the roughened film

B‧‧‧ Section line length of the surface of the conductive substrate

FIG. 1 is a schematic cross-sectional view of a representative lead frame material according to the present invention.

FIG. 2 is a diagram for explaining a method of calculating the specific surface area of the roughened layer.

FIG. 3 is a diagram for explaining the maximum width Wmax and the minimum width Wmin of the protrusions constituting one roughened layer.

FIG. 4 is a schematic cross-sectional view of another lead frame material according to the present invention.

FIG. 5 is a diagram for explaining the maximum width Wmax and the minimum width Wmin of the protrusions constituting the two roughened layers.

Next, the lead frame material according to the present invention is exemplified by specific embodiments, and described below with reference to the drawings. FIG. 1 is a schematic cross-section of a representative lead frame material according to the present invention. Symbols in FIG. 1 are a conductive substrate, a 2 roughened layer, a 3 roughened film, a 4 protrusion, and a 10 lead.架 材料。 Frame material. The lead frame material 10 of the present invention includes a conductive substrate 1 and a roughened film 3 including at least one roughened layer 2.

(Conductive substrate)

The conductive substrate 1 may be any material having conductivity, and examples thereof include copper, copper alloys, iron, iron alloys, aluminum, and aluminum alloys. Copper alloys, iron alloys, or aluminum alloys are preferred. In the lead frame material, it is particularly desirable to use a copper alloy that has a good balance of conductivity and strength because it needs to have strength capable of withstanding deformation such as bending during bonding with a semiconductor element. Among them, as the copper alloy, for example, "C14410 (Cu-0.15Sn, manufactured by Furukawa Electric Corporation, trade name: EFTEC (registered trademark) -3)", "C19400 ( Cu-Fe-based alloy material, Cu-2.3Fe-0.03P-0.15Zn "," C18045 (Cu-0.3Cr-0.25Sn-0.2Zn, manufactured by Furukawa Electric Industries, Ltd., trade name: EFTEC (registered trademark) -64T ) "," C50710 (Cu-2.0Sn-0.2Ni-0.05P), manufactured by Furukawa Electric Industries, Ltd., trade name: MF202 "," C70250 (Cu-3Ni-0.65Si-0.15Mg), manufactured by Furukawa Electric Industries, Ltd., Trade name: EFTEC (registered trademark) -7025 "and so on. The unit of the number shown before each element is "mass%". For use of such copper alloys, it is preferable to use strips of the following copper alloys: the tensile strength is 350 ~ 800N / mm ² , preferably 500 ~ 800N / mm ² , and the conductivity is 30 ~ 90% IACS. 50 ~ 80% IACS is better. In addition, the above "% IACS" refers to the electrical conductivity expressed when the resistivity of International Annealed Copper Standard 1.7241 × 10 ^-8 Ωm is 100% IACS, for example, the conductivity of "50% IACS", Refers to 50% of the electrical conductivity of IWC Standard Soft Copper.

Examples of the iron alloy include 42 alloy (Fe-42% by mass Ni) and stainless steel. The conductivity of the conductive substrate 1 containing the above-mentioned iron alloy is not so high, and it can be applied to a lead frame material 10 whose conductivity is not so required and for the purpose of transmitting electrical signals.

In the case of an aluminum alloy, an Al-Mg-based alloy such as A5052 may be mentioned.

Since a resin-sealed semiconductor device easily accumulates heat through a casting resin, it is important to dissipate heat inside the conductive substrate. In the present invention, by forming a roughened film on the surface of the conductive substrate, the heat dissipation effect can be improved compared with a case where no roughened film is formed, and at the same time, the conductive substrate can be thinned to 0.05 mm. If the thickness of the conductive substrate is thinner than 0.05 mm, sufficient heat dissipation cannot be achieved. On the other hand, if the thickness of the conductive substrate is 2 mm or more, miniaturization of the semiconductor device cannot be achieved. Therefore, the thickness of the conductive substrate 1 is preferably 0.05 to 2 mm, and more preferably 0.1 to 1 mm.

(Roughened film)

The roughened film 3 is formed on at least one side of the conductive substrate 1 and directly or through an intermediate layer (not shown), and at least one roughened layer 2 formed by a plurality of roughened particle protrusions 4 is formed. .

In addition, the roughened film 3 may be constituted by at least one roughened layer 2. However, considering the complexity of the manufacturing steps and the like, the roughened layer 2 is preferably constituted by 1 to 3 layers. In the method for forming the roughened film 3, after the roughened layer 2-1 of the first layer is formed, one or more factors such as composition or formation conditions are laminated on the roughened layer 2-1 of the first layer and the first factor is formed. The roughened layer 2 of the second layer is different from the roughened layer 2-2 of the second layer, which is formed by so-called multiple roughening, which can be a relatively thin film thickness and effectively increase the specific surface area to become better (refer to the figure) 4). In the present invention, the film thickness of the roughened film 3 is not measured locally, but at least by a fluorescent X-ray method (for example, a film thickness measuring device such as SFT9400 (trade name) manufactured by SII), The average film thickness at the time of measuring any three points of the collimator diameter of 0.2 mm or more is shown. When the roughened film 3 is composed of a plurality of roughened layers 2, the total thickness of the entire layer is defined as the thickness of the roughened film 3.

In addition, the film thickness of the roughened film 3 is not particularly limited, but the larger the film thickness, the larger the unevenness caused by the roughening tends to become large. Therefore, in order to make the roughened shape larger, the lower limit value of the thickness of the roughened film 3 is preferably 0.2 μm or more, more preferably 0.5 μm or more, and even more preferably 0.8 μm or more. On the other hand, if the thickness of the roughened film 3 exceeds 3 μm, there is a possibility that the so-called “powder dropping” that the roughened film 3 falls off during transportation may increase. Therefore, the upper limit of the thickness of the roughened film 3 is preferably 3 μm or less, more preferably 2 μm or less, and even more preferably 1.5 μm or less.

[Roughened layer]

The roughened layer 2 is formed by a plurality of protrusions 4 of roughened particles.

The method for forming the roughened layer 2 may be various methods such as wet plating and dry plating. From the viewpoint of being able to be easily and inexpensively formed, it is particularly preferable to form the layer by electroplating.

The roughened layer 2 includes, for example, a member selected from the group consisting of copper, copper alloy, nickel, nickel alloy, palladium, palladium alloy, silver, silver alloy, tin, tin alloy, zinc, zinc alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy Metals or alloys of the group consisting of iridium, iridium and iridium alloys are preferred. When the roughened layer 2 is formed on the roughened film 3 and a surface film (not shown) described later is further formed, from the viewpoint of improving the adhesion to the surface film, it contains copper, copper alloy, nickel, or Nickel alloys are preferred. For example, a copper-tin alloy, a copper-zinc alloy is used as the copper alloy, and a nickel-zinc alloy, a nickel-tin alloy, or the like is used as the nickel alloy.

The main feature of the structure of the present invention is to optimize the cross-sectional shape of the protrusions 4 constituting the roughened particles of the roughened layer 2. More specifically, as shown in FIG. 3, the protrusions 4 is controlled so as to have a maximum width Wmax when measured in the thickness direction section of the roughened film 3, and when measured at a position on the lower side of the conductive substrate 1 side relative to the measurement position of the maximum width Wmax The minimum width Wmin is 1 to 5 times the shape.

In this system, as a result of intensive research by the present inventors, assuming that the roughened layer is formed with the same surface roughness, the resin has a high shear strength (bonding strength) in a shear test, and good resin adhesion can be obtained. However, after a high-temperature and high-humidity durability test, for example, under high-temperature and high-humidity tests under the severe conditions of 168 hours in an environment with a temperature of 85 ° C and a humidity of 85%, it was found that among the roughened layers having the same surface roughness, There is a case where the shear strength is significantly reduced, and good resin adhesion cannot be maintained. Regarding this point, as a result of further investigation, it was found that the cross-sectional shape of the protrusions of the roughened particles forming the roughened layer was greatly affected. It was found that, particularly at the smallest width of the protrusions, the The stress concentration caused by thermal expansion or contraction will reduce the adhesion.

Therefore, the present inventors conducted further detailed studies and found that the ratio of the maximum width to the minimum width of the protrusions of the roughened particles forming the roughened layer of the roughened film was 1 to 5, that is, The protrusions are controlled to have a maximum width when measured in a thickness direction cross section of the roughened film, and a minimum width when measured in a lower portion closer to the conductive substrate than the measurement position of the maximum width. It has a shape of 1 to 5 times. Among roughened layers with the same degree of surface roughness, even in high-temperature and high-humidity durability tests, such as 168 hours in an environment with a temperature of 85 ° C and a humidity of 85%. After the high-temperature and high-humidity test is performed under severe conditions, the resin's shear strength (bonding strength) is hardly reduced, and good resin adhesion can be maintained.

In the protrusion, the so-called maximum width is twice the minimum width, which means that the maximum width is the same as the minimum width, and the shape of the protrusion may be, for example, a substantially cylindrical shape or an angular column shape. On the other hand, if the maximum width of the protrusion exceeds 5 times the minimum width, the stress concentration due to the expansion or contraction of the resin will increase at the minimum width of the protrusion forming the roughened layer. However, the anchoring effect cannot be effectively exerted, and it is easy to break at the smallest width of the protrusion. Therefore, the maximum width of the protrusion is made 1 to 5 times the minimum width. In addition, not only the casting resin can exert the anchoring effect, it is not easy to break at the smallest part of the protrusion of the resin to form a roughened layer, which can not only improve the shear strength of the lead frame material, but also enhance the vertical direction when needed In the case of tensile strength, the ratio of the maximum width to the minimum width of the protrusion is preferably 1.1 to 4.9 times, more preferably 1.2 to 4.8 times, more preferably 1.5 to 4.0 times, and 1.5 to 3.0. Times best. Furthermore, the shape of the surface of the protrusion may be sharp or smooth. What is important is the ratio of the maximum width to the minimum width of the protrusion.

<Definition of maximum width and minimum width of protrusions>

In the present invention, the maximum width and the minimum width of the protrusions can be processed, for example, by focusing ion beam (Focused Ion Beam, FIB) or mechanical grinding, to process the lead frame material forming the roughened layer to make a vertical section. Next, the roughened layer of the vertical cross-section sample is observed with a light microscope or a scanning electron microscope, and the line segment is moved in parallel from the surface of the conductive substrate to the surface of the roughened layer. For a plurality of protrusions, determine the width of each protrusion, and determine the maximum (maximum width) Wmax and minimum (minimum width) Wmin. To explain in more detail, as shown in FIG. 3, when a vertical line is drawn from the conductive substrate 1 in the direction of the roughened layer, and the direction from the apex to the conductive substrate 1 is scanned with a line (parallel line) parallel to the substrate, it is determined. The width of the maximum value of the display protrusions 4 is taken as the maximum width Wmax. When scanning from the position of the maximum width Wmax to the conductive substrate 1 in parallel lines, the width of the minimum value of the display protrusions 4 is determined as The minimum width Wmin. Then, in the present invention, the value of the ratio Wmax / Wmin must be 1 to 5.

In addition, the minimum width Wmin of the protrusions 4 refers to the measurement position of the maximum width Wmax of the protrusions 4 when measured in the thickness direction section of the roughened film 3, and is located closer to the conductive substrate 1 side. The minimum width Wmin when measured at the lower part of. This is based on the insight that the shear strength is affected by the width of the lower portion (base end portion) of the protrusion 4 on the conductive substrate 1 side in the shear test. In addition, in order to observe an arbitrary cross section of the protrusion 4, observation was performed at various positions of the roughened layer 2. In this system, since the roughened layer 2 is generally formed in three dimensions, the roughened layer 2 that measures the maximum width Wmax and the minimum width Wmin of the protrusion 4 is a roughened layer 2 of one layer, or The roughened layer of two or more layers shown in FIG. 5 (for example, two roughened layers 2-1 and 2-2 in FIG. 5), and the maximum width Wmax and the minimum width of the protrusion 4 can be measured. In the case of Wmin, other than the measurement target, for example, when the outermost contour of the roughened film 3 with two or more roughened layers is not clear, or when the roughened layer 2 appears to float from the conductive substrate 1 Etc. In the present invention, a roughened layer that cannot be a measurement target. By these methods, the maximum width Wmax and the minimum width Wmin of the ten protrusions 4 existing in one roughened layer 2 are measured at an arbitrary cross section, respectively, and the maximum width Wmax versus the minimum width Wmin is calculated. The ratio Wmax / Wmin is defined as the lead frame material 10 having the roughened layer 2 having an average value of 1 to 5 times the above ratio as the lead frame material of the present invention.

<About the minimum width of the protrusions and the distance between the protrusions>

In addition, the minimum width Wmin of the protrusions 4 forming the roughened layer 2 in the present invention is not particularly limited. If the minimum width Wmin is too small, it is difficult for the resin to be between the protrusions 4 of the roughened layer 2. On the other hand, if the minimum width Wmin is too large, the effect of increasing the shear strength tends to be small. Therefore, the minimum width Wmin of the protrusions 4 is preferably in the range of 0.2 μm to 3 μm on average, and more preferably in the range of 0.5 μm to 1 μm. The distance between the protrusions 4 is not particularly limited, but the average distance between the apexes of the protrusions 4 and the protrusions 4 is preferably in a range of 0.2 to 20 μm, and more preferably in a range of 0.5 to 10 μm.

<About the specific surface area of the roughened layer>

In the lead frame material 10 of the present invention, first, a conductive substrate (hereinafter, also referred to simply as a "substrate") 1 has a roughened layer 2. The specific surface area of the roughened layer 2 is preferably 110% or more. This is because if the specific surface area is less than 110%, the anchoring effect cannot be sufficiently obtained. In addition, there is no particular limitation on the upper limit of the specific surface area, but if the specific surface area is too large, the roughened unevenness becomes large, and the roughened layer easily falls off. Therefore, the specific surface area is preferably 500% or less.

In addition, the calculation method of the specific surface area is shown in the cross-section of the lead frame material 10 shown in FIG. 2. Please refer to the cross-section of the lead frame material 10 to roughen the line segment length of the outermost layer of the film 3 (the dotted line A in FIG. 2). The ratio A / B divided by the (straight) length (the thick solid line B in FIG. 2) of the surface of the conductive substrate 1 is the specific surface area (%). For example, a non-contact interference microscope can be used. (For example, manufactured by BRUKER AXS). In addition, the formation place of the roughened layer of the present invention may be formed on at least a part of the portion through the resin mold, and of course, the roughened layer 2 may be partially processed. In addition, for example, it is preferable to form at least 1/5 or more of the portion of the lead frame material 10 through the resin mold, and more preferably to form an area of 1/2 or more, so that the effect of improving adhesion can be exhibited. Preferably, the roughened layer 2 is formed over the entire surface of the resin mold. The shape of the roughened layer 2 provided in this portion may be various shapes such as a line shape, a dot shape, and a ring shape. In addition, the resin mold is only included in a single-sided product, and for example, the roughened layer 2 may be formed only on a single-sided product.

(middle layer)

In addition, the lead frame material 10 of the present invention may form an intermediate layer between the conductive substrate 1 and the roughened film 3, for example, to suppress the diffusion of constituent components constituting the conductive substrate 1 or to improve adhesion. The intermediate layer may be, for example, nickel, a nickel alloy, cobalt, a cobalt alloy, copper, or a copper alloy.

(Surface film)

In addition, the lead frame material 10 of the present invention is preferably provided on at least a part of the surface of the roughened film 3 directly or via an intermediate layer, and further includes a surface film containing at least one layer, and the surface coating layer preferably contains A metal or alloy selected from the group consisting of palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver, and silver alloy.

[Surface coating layer]

Various alloys constituting the surface coating layer include, for example, palladium-silver alloy as a palladium alloy, rhodium-palladium alloy as a rhodium alloy, ruthenium-iridium alloy as a ruthenium alloy, platinum-gold alloy as a platinum alloy, and Platinum-iridium alloys of iridium alloys, gold-silver alloys as gold alloys, silver-tin alloys as silver alloys, and the like. The surface film may be one type, but two or more layers are preferable. The typical layer structure when the surface coating layer constituting the surface film is two or more layers, the lamination order from the 3 sides of the roughened film, for example, Pd / Au, Rh / Au, Pd / Ag / Au , Pd / Rh / Au, Ru / Pd / Au, etc. By forming the surface film layer on the roughened film in this way, the heat resistance of the lead frame can be improved, and at the same time, the strength of the protrusions of the roughened particles forming the roughened layer of the roughened film can be increased, and the protrusions can be prevented. Fracture, further exert the anchoring effect. In addition, from the viewpoint of improving the adhesion to the surface film, the surface film layer is preferably two layers of Pd / Au or two layers of Rh / Au, compared to two layers of copper and nickel whose roughened layer is; The layer structure of the roughened layer, the lower roughened layer is copper, and the upper roughened layer is nickel. On the other hand, as the layer structure of the surface coating layer, the lower surface coating layer is more preferably Pd, and The upper surface coating layer is two layers of Au, or the lower surface coating layer is Rh, and the upper surface coating layer is two layers of Au.

If the thickness of these surface coatings is too thick, the surface of the roughened film 3 will be buried, so that the effects of the present invention cannot be fully exerted. In addition, the surface film is mainly composed of heavy metal materials, which may increase the cost. . Therefore, the film thickness of each surface coating layer is preferably 1 μm or less, and more preferably 0.03 or less as the total film thickness (film thickness of the surface film) of the laminated surface coating layer.

(About manufacturing method of lead frame material)

Next, the manufacturing method of the lead frame material 10 of this invention is demonstrated below.

A conductive substrate 1 is prepared, and the conductive substrate 1 is subjected to a cathodic electrolytic degreasing step and an acid washing step. Next, as required, after forming the intermediate layer by electroplating, a roughened film 3 including at least one roughened layer 2 is formed by electroplating, and then, if necessary, an electrode with at least one surface coating layer is formed by electroplating. The surface film can be used to manufacture the lead frame material 10. As representative examples of specific manufacturing conditions, the cathode electrolytic degreasing conditions are shown in Table 1, the pickling conditions are shown in Table 2, the formation conditions of various intermediate layers are shown in Table 3, and various roughened layers are shown in Table 4. The forming conditions of 2 and Table 5 show the forming conditions of various surface coating layers. In the manufacturing method of the lead frame material 10 described above, the case where the intermediate layer, the roughened layer 2 and the surface coating layer are all manufactured by electroplating is exemplified. The roughened layer 2 is relatively easy to control the shape of the protrusions by current density, agitation, temperature, processing time, and the like, and is therefore preferably formed by electroplating. Furthermore, regarding the intermediate layer or the surface coating layer, It can also be formed by a wet plating method such as an electroplating method, which is preferable from the viewpoint of productivity, but can also be manufactured by a dry plating method or other manufacturing methods, and is not particularly limited.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

Various conductive substrates shown in Table 6 which were cut into a test piece size of 40 mm × 40 mm and a thickness of 0.2 mm were prepared in advance, and cathodic electrolytic degreasing was performed under the conditions shown in Table 1 above. Next, after pickling the conductive substrate under the conditions shown in Table 2, at least one roughened layer was formed on the surface of the conductive substrate with the layer configuration shown in Table 6 to obtain a test piece of a lead frame material. In addition, the formation of the roughened layer is not only the specific surface area, but also the ratio of the maximum width to the minimum width in the protrusions of the roughened layer in the cross section. Among Examples 1 to 30, in Examples 11 to 13, a roughened film was added to the lower roughened layer to further form an upper roughened layer, and the roughened layer was composed of two roughened layers. In Examples 22 to 24, an intermediate layer was further formed between the conductive substrate and the roughened film. Then, regarding Examples 29 and 30, a roughened film was added to the lower roughened layer to further form an upper roughened layer. A two-layer roughened layer is formed, and at the same time, a two-layer surface film including a lower surface coating layer and an upper surface coating layer is further formed. For reference, as Comparative Example 1, the specific surface area of the roughened layer is 550% and is very large, but the ratio of the maximum width to the minimum width of the protrusions forming the roughened layer is not controlled, and is further produced in the present invention. The test piece of the lead frame material outside the range (5.2 times).

In each of the above test pieces, a resin mold was injection-molded using a transfer mold test device (product name: Model FTS) manufactured by Kohtaki Seiki Co., Ltd. at a mold temperature of 130 ° C, a retention time of 90 seconds after the mold, and an injection pressure of 6.865 MPa. A pudding-like test piece having a contact area of 10 mm ² was formed. This test piece was put into a high-temperature and high-humidity test (85 ° C, 85% RH, and maintained for 168 hours), and the test piece was evaluated for resin adhesion and powder-removing property under the following conditions. The evaluation results are shown in Table 7.

(Resin adhesion evaluation)

Evaluation resin: G630L, manufactured by Sumitomo Bakelite (trade name)

Evaluation conditions: Device: 4000Plus, made by Nordson Advanced Technology (trade name),

Load element: 50kg

Measurement range: 10kg

Test speed: 100μm / s

Test height: 10μm

Table 7 shows the evaluation results of the resin adhesion. In addition, the evaluation of the adhesiveness of the resin shown in Table 7 indicates that when the average shear strength (peeling strength) is 9.8 MPa or more, the resin is excellent in adhesiveness and is represented by "A". The average shear strength (peeling strength) is When 4.9 MPa or more is less than 9.8 MPa, the resin adhesion is good and expressed as "B". Then, when the shear strength (peel strength) is less than 4.9 MPa on average, the resin adhesion is poor and expressed as "C".

Resin adhesion was evaluated by measuring both the "initial shear strength" and the "shear strength after the high temperature and high humidity test". The "shear strength after the high temperature and high humidity test" is a value obtained after the resin of each test piece is cast and left in an environment at a temperature of 85 ° C and a humidity of 85% for 168 hours. The "initial shear strength" refers to the shear strength after the resin of each test piece is cast (before the high temperature and high humidity test).

(Evaluation of powder loss)

Powder loss is based on visual assessment of sensitivity. The evaluation results are shown in Table 7. In addition, among the powder-falling properties shown in Table 7, when no powder-falling from the surface was observed, it was represented by "A (excellent)", and when a little powder-falling occurred, it was represented by "B (good)". When the powder is dropped, it is expressed as "C (not allowed)", and "A" and "B" are available at a practical level.

As can be seen from the evaluation results in Table 7, in Examples 1 to 30, both the initial shear strength and the shear strength after the high-temperature and high-humidity test were "A" or "B", maintaining good resin adhesion. The powderiness is also "A" or "B" and can be used at a practical level. In contrast, although the specific surface area of the roughened layer is 550% and is very large, the ratio of the maximum width to the minimum width of the protrusions forming the roughened layer is not controlled, and is outside the scope of the present invention (5.2 times Comparative Example 1) Although the initial shear strength is "A" and the resin is excellent in adhesiveness, the shear strength after the high-temperature and high-humidity test becomes "C", the resin adhesiveness is greatly deteriorated, and the powder-falling property is also A poor "C" is not a practical level.

[Industrial profitability]

The lead frame material of the present invention can maintain the good quality of the lead frame even when subjected to the high temperature and high humidity endurance test, for example, under severe conditions where the temperature is 85 ° C and the humidity is 85%, and is placed for 168 hours. The resin has almost no deterioration in adhesiveness, and a semiconductor package made of the lead frame material can achieve high reliability.

Claims (7)

    A lead frame material includes: a conductive substrate; and a roughened film, which is included on at least one side of the conductive substrate, directly or via an intermediate layer, at least one layer formed by a plurality of roughened particle protrusions. The formation layer, in which the protrusion has a maximum width when measured in a thickness direction cross-section of the roughened film, and is located at a lower portion closer to the conductive substrate than a measurement position of the maximum width. The smallest width at the time of measurement is 1 to 5 times.         The lead frame material according to item 1 of the patent application scope, wherein the conductive base system is copper, copper alloy, iron, iron alloy, aluminum, or aluminum alloy.         The lead frame material according to item 1 or 2 of the scope of patent application, wherein the roughened layer comprises a material selected from the group consisting of copper, copper alloy, nickel, nickel alloy, palladium, palladium alloy, silver, silver alloy, tin, tin alloy, A metal or alloy of the group consisting of zinc, zinc alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, iridium and iridium alloy.         The lead frame material according to any one of claims 1 to 3, wherein at least a part of the surface of the roughened film further includes a surface film including at least one surface coating layer, and the surface coating The coating comprises a metal or alloy selected from the group consisting of palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver, and silver alloy.         The lead frame material according to item 4 of the scope of patent application, wherein the intermediate layer is nickel, nickel alloy, cobalt, cobalt alloy, copper or copper alloy.         A method for manufacturing a lead frame material, comprising the step of forming a roughened film, the roughened film being included on at least one side of the conductive substrate, directly or via an intermediate layer, by plating with a plurality of roughened particle protrusions At least one roughened layer formed by an object, wherein the protrusion has a maximum width when measured in a thickness direction cross section of the roughened film, and is located closer to the conductive layer than a measurement position of the maximum width. The minimum width at the time of measurement of the lower part of the sex substrate side is 1 to 5 times.         A semiconductor package includes the lead frame material according to any one of claims 1 to 5.