JP6479265B2 - Lead frame material, manufacturing method thereof, and semiconductor package - Google Patents

Description

  The present invention relates to a lead frame material suitable for use in a resin-encapsulated semiconductor device in which a semiconductor element and a lead frame having a surface treatment layer are electrically connected to each other and sealed with a mold resin. The present invention relates to a manufacturing method and a semiconductor package.

  This type of resin-encapsulated semiconductor device has a structure in which a semiconductor element and a lead frame that are electrically connected to each other by a wire or the like are sealed with a mold resin. Such a resin-encapsulated semiconductor device is manufactured by subjecting a lead frame to surface treatment such as exterior plating and forming a surface film with a Sn alloy such as a Sn-Pb alloy or a Sn-Bi alloy. Is common.

  Here, in recent years, in order to simplify the assembly process and reduce the cost, plating having a specification that improves wettability with solder in advance on the surface of the lead frame by solder or the like on the printed circuit board (for example, Ni / Pd / Au) is beginning to be adopted (Pre-Plated Frame) (for example, see Patent Document 1).

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

  The technology for roughening the plating surface is to roughen the surface by subjecting the lead frame to roughening, and (1) the mold resin enters the irregularities of the roughened plating film to form a strong mechanical joint. The effect (anchor effect), (2) improvement in chemical bonding due to improvement in the contact area between the mold resin and the plating surface are expected.

  By roughening the surface of the lead frame, the adhesion of the mold resin to the lead frame is improved, and the separation between the lead frame and the mold resin is suppressed. As a result, the reliability of the resin-encapsulated semiconductor device is improved. Can be made.

Japanese Patent Laid-Open No. 4-115558 JP-A-6-029439

  By roughening the surface of the lead frame, it is possible to improve the adhesion of the mold resin to the lead frame as compared with the conventional resin-encapsulated semiconductor device. However, in recent years, the required level for reliability has become more severe than before, and durability tests of high temperature and high humidity, for example, severe conditions of leaving for 168 hours in an environment of temperature 85 ° C. and humidity 85% Even if a high-temperature and high-humidity test is performed, it is necessary to clear the acceptance criteria for reliability. On the other hand, in the conventional configuration in which the surface of the lead frame is simply roughened as in Patent Document 1, there is a case where a gap is generated between the resin and the lead frame, and the acceptance criteria for reliability may not be cleared. This is because, as resin-encapsulated semiconductor devices, packages such as a QFN (Quad Flat Non-Leaded Package) type and an SOP (Small Outline Package) type have been used in recent years. This is thought to be because the level of demand for the adhesiveness of this material has become even higher. As described above, in the resin-encapsulated semiconductor device, regarding the adhesiveness of the resin to the lead frame, it has been required to maintain good adhesiveness even under the severe conditions described above. Therefore, it was necessary to further improve.

  The present invention is a lead frame suitable for forming a lead frame surface capable of maintaining good resin adhesion even when a high-temperature and high-humidity test is performed under the severe conditions described above. It is an object to provide a material, a manufacturing method thereof, and a highly reliable semiconductor package.

  The present inventors have intensively studied to solve the above-mentioned problems, and the cross-sectional shape of the projections of the roughened particles constituting the roughened layer of the roughened film formed on the conductive substrate is resin adhesion. Good adhesion caused by the so-called anchor effect, which is caused by filling and forming the resin on the uneven surface (particularly the concave portion) due to the protrusions formed on the surface of the lead frame material. It was investigated whether it could be maintained even when the high temperature and high humidity test was conducted under the above severe conditions.

  Then, the inventors measured the protrusion forming the roughened layer of the roughened film formed on the conductive substrate, the maximum width when measured in the cross section in the thickness direction of the roughened film, the maximum width By controlling to have a shape that is 1 to 5 times the minimum width when measured at the lower part located on the conductive substrate side relative to the measurement position, the minimum width of the projection of roughened particles in particular It was found that the peeling phenomenon caused by the shearing of the resin, which is likely to occur due to the stress concentration due to the expansion or contraction of the resin, can be effectively suppressed. As a result, good adhesion due to the anchor effect can be maximized by the roughened layer, and further, by controlling the protrusions forming the roughened layer to the above shape, it cannot be endured conventionally. Even when a high temperature and high humidity durability test is conducted, for example, when a high temperature and high humidity test is performed under harsh conditions of 168 hours in an environment of a temperature of 85 ° C. and a humidity of 85%, it is a good resin for the lead frame. It has been found that adhesion can be maintained.

That is, the gist configuration of the present invention is as follows.
(1) A roughened film comprising a conductive substrate and at least one roughened layer formed of protrusions of a plurality of roughened particles directly or via an intermediate layer on at least one surface of the conductive substrate. With
The protrusion has a maximum width when measured in a cross section in the thickness direction of the roughened film, and a minimum width when measured at a lower portion located on the conductive substrate side than the measurement position of the maximum width. A lead frame material having a shape that is 1 to 5 times as large.
(2) The lead frame material according to (1), wherein the conductive substrate is copper, copper alloy, iron, iron alloy, aluminum, or aluminum alloy.
(3) The roughening layer is made 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, iridium. And the lead frame material according to (1) or (2) above, comprising a metal or alloy selected from the group of iridium alloys.
(4) A surface film including at least one surface coating layer is further provided on at least a part of the surface of the roughened film, and the surface coating layer includes palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, The ruthenium alloy, platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver or a metal or an alloy selected from the group of silver alloys, according to any one of (1) to (3) above Lead frame material.
(5) The lead frame material according to (4), wherein the intermediate layer is nickel, nickel alloy, cobalt, cobalt alloy, copper, or copper alloy.
(6) A roughened film including at least one roughened layer formed of protrusions of a plurality of roughened particles is formed by electroplating directly or via an intermediate layer on at least one surface of the conductive substrate. The protrusion has a maximum width when measured in the cross section in the thickness direction of the roughened film, and the protrusion is measured at a lower portion located on the conductive substrate side than the measurement position of the maximum width. A method for manufacturing a lead frame material having a shape that is 1 to 5 times the minimum width.
(7) A semiconductor package having the lead frame material according to any one of (1) to (5) above.

  The lead frame material of the present invention comprises a conductive substrate and at least one roughened layer formed of a plurality of roughened particle projections directly or via an intermediate layer on at least one surface of the conductive substrate. A roughened film including the protrusion, and the protrusion has a maximum width when measured in a cross-section in the thickness direction of the roughened film, the lower side being positioned closer to the conductive substrate than the measurement position of the maximum width By having a shape that is 1 to 5 times the minimum width when measured in a part, the durability test of high temperature and high humidity, for example, harsh conditions of leaving for 168 hours in an environment of temperature 85 ° C. and humidity 85% Even when a high-temperature and high-humidity test is performed under this condition, good resin adhesion to the lead frame can be maintained with almost no deterioration, and the semiconductor package constructed using this lead frame material has high reliability. Realize It is possible.

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 will be described below with reference to the drawings by giving examples of specific embodiments. FIG. 1 is a schematic cross-sectional view of a typical lead frame material according to the present invention. Reference numeral 1 in FIG. 1 denotes a conductive substrate, 2 denotes a roughened layer, 3 denotes a roughened film, and 4 denotes a protrusion. , And 10 is a lead 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 alloy, iron, iron alloy, aluminum, and aluminum alloy, and copper alloy, iron alloy, and aluminum alloy are preferable. For the lead frame material, it is particularly preferable to use a copper alloy having a good balance between conductivity and strength, since the lead frame material is required 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 Co., Ltd., trade name: EFTEC (registered trademark) -3)” which is a CDA (Copper Development Association) listed alloy, “C19400” (Cu-Fe alloy material, Cu-2.3Fe-0.03P-0.15Zn) "," C18045 (Cu-0.3Cr-0.25Sn-0.2Zn, manufactured by Furukawa Electric Co., Ltd., trade name: EFTEC (registered trademark) -64T) "," C50710 (Cu-2.0Sn-0.2Ni-0.05P), manufactured by Furukawa Electric Co., Ltd., trade name: MF202 "," C70250 (Cu-3Ni-0.65Si) -0.15Mg), manufactured by Furukawa Electric Co., Ltd., trade name: EFTEC (registered trademark) -7025 ", and the like. The unit of the numbers shown immediately before each element is “mass%”. Like these copper alloys, copper having a tensile strength of 350 to 800 N / mm ² , preferably 500 to 800 N / mm ² and a conductivity of 30 to 90% IACS, preferably 50 to 80% IACS It is preferred to use alloy strips. The above-mentioned “% IACS” represents the electrical conductivity when the resistivity 1.7241 × 10 −8 Ωm of universal standard soft copper (International Annealed Copper Standard) is 100% IACS. For example, “50% The conductivity of “IACS” means 50% of the conductivity of universal standard annealed copper.
In the case of an iron alloy, for example, 42 alloy (Fe-42 mass% Ni), stainless steel, and the like can be given. The conductive substrate 1 containing such an iron alloy has a low conductivity, but does not require a high conductivity, and can be applied to a lead frame material 10 for the purpose of transmitting electrical signals.
Furthermore, in the case of an aluminum alloy, for example, an Al—Mg alloy such as A5052 can be used.
Since the resin-encapsulated semiconductor device easily retains heat due to the mold resin, it is important to dissipate the internal heat through 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 as compared with the case where the roughened film is not formed, and the conductive substrate is thin to 0.05 mm. It became possible. If the thickness of the conductive substrate is less 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. For this reason, 0.05-2 mm is preferable and, as for the thickness of the electroconductive base | substrate 1, 0.1-1 mm is more preferable.

(Roughening film)
The roughened film 3 is at least one roughened layer 2 formed of a plurality of roughened particle projections 4 directly or via an intermediate layer (not shown) on at least one surface of the conductive substrate 1. It is configured.
Moreover, the roughening film 3 should just be comprised with the at least 1 layer of roughening layer 2, However, when the complexity of a manufacturing process etc. are considered, it is preferable to comprise with the roughening layer 2 of 1-3 layers. The formation method of the roughening film 3 includes two layers in which one or more factors such as composition and formation conditions are different from those of the first roughening layer 2-1 after forming the first roughening layer 2-1. The specific surface area can be effectively increased with a relatively thin film thickness by forming the roughened layer 2-2 of the eye on the first roughened layer 2-1, by so-called multiple roughening. This is more preferable because it can be performed (see FIG. 4). In the present invention, the film thickness of the roughened film 3 is not measured locally, but at least by the fluorescent X-ray method (for example, a film thickness measuring device such as SFT9400 (trade name) manufactured by SII). The average film thickness when measured at three arbitrary points at 0.2 mm or more is used. When the roughened film 3 is composed of a plurality of roughened layers 2, the total thickness of all the layers is defined as the thickness of the roughened film 3.
Moreover, the film thickness of the roughening film 3 is not particularly limited, but the larger the film thickness, the larger the unevenness due to the roughening. Therefore, in order to increase the roughened shape, the lower limit value of the film thickness of the roughened film 3 is preferably 0.2 μm or more, more preferably 0.5 μm or more, and further preferably 0.8 μm or more. On the other hand, when the film thickness of the roughened film 3 exceeds 3 μm, there is a concern that the roughened film 3 may drop off during transportation, so-called “powder falling”. For this reason, the upper limit of the film thickness of the roughening film 3 is preferably 3 μm or less, more preferably 2 μm or less, and still more preferably 1.5 μm or less.

[Roughening layer]
The roughened layer 2 is formed of a plurality of roughened particle projections 4.
The roughening layer 2 may be formed by various methods such as wet plating and dry plating, but is preferably formed by electroplating from the viewpoint that it can be formed easily and inexpensively.
The roughening layer 2 is made of, for example, copper, copper alloy, nickel, nickel alloy, palladium, palladium alloy, silver, silver alloy, tin, tin alloy, zinc, zinc alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, iridium and iridium. Preferably it comprises a metal or alloy selected from the group of alloys. In the case of forming a surface film (not shown), which will be described later, on the roughened film 3, the roughened layer 2 is preferably made of copper, copper alloy, nickel or nickel from the viewpoint of improving adhesion to the surface film. More preferably, an alloy is included. Examples of the copper alloy include a copper-tin alloy, a copper-zinc alloy, and examples of the nickel alloy include a nickel-zinc alloy and a nickel-tin alloy.

  The main feature of the structure of the present invention is to optimize the cross-sectional shape of the projections 4 of the roughened particles constituting the roughened layer 2, more specifically, the projections 4 are formed as shown in FIG. As shown in FIG. 4, the maximum width Wmax when measured in the cross section in the thickness direction of the roughened film 3 is the maximum when measured at the lower portion located on the conductive substrate 1 side than the Wmax measurement position of the maximum width. The control is to have a shape that is 1 to 5 times the small width Wmin.

  As a result of intensive studies by the present inventors, if the roughened layer is formed with the same surface roughness, the shear strength (bonding strength) of the resin in the shear test is high, and good resin adhesion is obtained. However, after performing a high temperature and high humidity durability test such as a high temperature and high humidity test under harsh conditions that are allowed to stand for 168 hours in an environment of 85 ° C. and 85% humidity, roughening with the same surface roughness is performed. It has been found that some of the layers have a shear strength that greatly decreases and cannot maintain good resin adhesion. As a result of further investigation on this point, it was found that the cross-sectional shape of the projections of the roughened particles forming the roughened layer is greatly affected, and the thermal expansion of the resin particularly at the location where the minimum width of the projections It was found that the stress due to the shrinkage was concentrated and the adhesion was lowered.

  For this reason, the present inventors proceeded with further detailed examination. As a result, the ratio of the maximum width and the minimum width of the projections of the roughened particles forming the roughened layer of the roughened film was 1 to 5, that is, the protrusions were The maximum width when measured in the cross section in the thickness direction of the roughened film is 1 to 5 times the minimum width when measured at the lower portion located on the conductive substrate side from the measurement position of the maximum width. In the roughened layer having the same degree of surface roughness, it is left to stand for 168 hours in an environment of high temperature and high humidity, for example, at a temperature of 85 ° C. and a humidity of 85%. It has been found that even after a high-temperature and high-humidity test under harsh conditions, good resin adhesion can be maintained with almost no decrease in the shear strength (bonding strength) of the resin.

  In the projection, the maximum width is one times the minimum width, which means that the maximum width and the minimum width are the same. Examples of the shape of the projection include a substantially cylindrical shape and a prismatic 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 and contraction of the resin increases at the minimum width of the protrusion forming the roughened layer, so the anchor effect is effective. Cannot be exerted easily, and breakage tends to occur at the minimum width portion of the protrusion. For this reason, the protrusion has a maximum width of 1 to 5 times the minimum width. In addition, the mold resin not only exhibits an anchoring effect, but the shear strength of the lead frame material is improved by making the resin less likely to break at the minimum portion of the protrusion forming the roughened layer. When the vertical tensile strength needs to be further improved, the ratio of the maximum width to the minimum width of the protrusion is preferably 1.1 to 4.9 times, and 1.2 to 4.8 times is more preferable, 1.5 to 4.0 times is more preferable, and 1.5 to 3.0 times is most preferable. In addition, although it is the shape of the surface in a protrusion, it may be sharply sharp or round and smooth, and the ratio of the maximum width and the minimum width of the protrusion is important.

<Definition of maximum width and minimum width of protrusions>
The maximum width and the minimum width of the protrusions in the present invention are prepared by processing a lead frame material on which a roughened layer is formed by a method such as Focused Ion Beam (FIB) or mechanical polishing, for example, Next, the roughened layer of the vertical cross-section sample is subjected to cross-sectional observation with an optical microscope, a scanning electron microscope, etc., and the line segment is translated from the surface of the conductive substrate toward the surface of the roughened layer to roughen the surface. For a plurality of protrusions forming a layer, the width is measured for each protrusion, and the maximum value (maximum width) Wmax and the minimum value (minimum width) Wmin are determined. More specifically, as shown in FIG. 3, a perpendicular line is drawn from the conductive substrate 1 in the direction of the roughened layer, and a line parallel to the substrate (parallel line) is scanned in the direction from the apex toward the conductive substrate 1. The width indicating the maximum value of the protrusion 4 when the protrusion is made is set as Wmax, and the minimum value of the protrusion 4 when the parallel line is further scanned in the direction from the position of the maximum width Wmax toward the conductive substrate 1 is set. The width shown is determined as Wmin as the minimum width. In the present invention, the value of the ratio Wmax / Wmin needs to be 1 to 5.
Note that the minimum width Wmin of the protrusion 4 is measured at a lower portion located on the conductive substrate 1 side than the measurement position of the maximum width Wmax of the protrusion 4 when measured in the cross section in the thickness direction of the roughened film 3. Means the minimum width Wmin. This is based on the knowledge that the shear strength depends on the width of the lower portion (base end portion) of the protrusion 4 located on the conductive substrate 1 side in the shear test. In addition, since the protrusion 4 observes arbitrary cross sections, it is observed in various positions of the roughening layer 2. This is because the roughened layer 2 is basically formed three-dimensionally, so that the roughened layer 2 for measuring the maximum width Wmax and the minimum width Wmin of the protrusion 4 is one layer. 5 or two or more roughened layers (for example, two roughened layers 2-1 and 2-2 in FIG. 5), and the protrusion 4 The case where the maximum width Wmax and the minimum width Wmin can be measured is used as a measurement object. Otherwise, for example, when there are two or more roughened layers and the outermost surface contour of the roughened film 3 is not clear, the conductive substrate 1 In the case of the roughened layer 2 that appears to float, the roughened layer that cannot be measured in the present invention is used. By these methods, the maximum width Wmax and the minimum width Wmin of each of the ten protrusions 4 existing in one roughened layer 2 are measured in an arbitrary cross section, and the ratio Wmax of the maximum width Wmax to the minimum width Wmin is measured. / Wmin is calculated, and the lead frame material 10 having the roughened layer 2 whose average value of the ratio is 1 to 5 times is defined as the lead frame material of the present invention.

<Minimum width of protrusions and spacing between protrusions>
Further, the size of the minimum width Wmin of the projection 4 forming the roughened layer 2 in the present invention is not particularly specified, but if the minimum width Wmin is too small, the resin is a projection 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. For this reason, the minimum width Wmin of the protrusion 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. Moreover, although it does not specifically limit about the space | interval of the protrusions 4 and 4, The range of 0.2-20 micrometers is preferable as an average space | interval of the vertexes of the protrusions 4 and 4, 0.5 micrometers-10 micrometers A range is further preferred.

<About the specific surface area of the roughened layer>
The lead frame material 10 of the present invention has a roughened layer 2 with respect to a conductive substrate (hereinafter also simply referred to as “substrate”) 1. The roughened layer 2 preferably has a specific surface area of 110% or more. This is because the anchor effect cannot be sufficiently obtained when the specific surface area is less than 110%. Although there is no particular restriction on the upper limit of the specific surface area, if the specific surface area is too large, the unevenness of the roughening becomes too large and the roughened layer tends to fall off, so the specific surface area should be 500% or less. Is preferred.

  In addition, as a calculation method of the specific surface area, as shown in the cross section of the lead frame material 10 in FIG. 2, the line segment length of the outermost layer of the roughened coating 3 (in FIG. 2) The percentage of the ratio A / B divided by the (straight) length of the surface of the conductive substrate 1 (thick solid line B in FIG. 2) becomes the specific surface area (%), for example, non-contact interference It can be measured using a measuring device such as a microscope (for example, manufactured by Bruker AXS). In addition, the roughened layer may be formed in at least a part of the resin-molded portion in the present invention, and the roughened layer 2 may be partially formed as well as the entire surface treatment. Good. Further, for example, the lead frame material 10 is preferably at least 1/5 or more of the portion to be resin-molded, and more preferably has an area of 1/2 or more, thereby exhibiting an effect of improving adhesion. . Most preferably, the roughened layer 2 is formed on the entire surface to be resin-molded. The shape of the partially provided roughening layer 2 can take various forms such as a stripe shape, a spot shape, and a ring shape. Furthermore, in a product in which the resin mold is only on one side, for example, the roughened layer 2 can be formed only on one side.

(Middle layer)
Further, the lead frame material 10 of the present invention forms an intermediate layer between the conductive substrate 1 and the roughened film 3 in order to suppress diffusion of composition components constituting the conductive substrate 1 and improve adhesion. May be. Examples of the intermediate layer include nickel, nickel alloy, cobalt, cobalt alloy, copper, and copper alloy.

(Surface film)
Further, the lead frame material 10 of the present invention preferably further includes a surface film including at least one surface coating layer directly or via an intermediate layer on at least a part of the surface of the roughened film 3. The surface coating layer includes a metal or alloy selected from the group of palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver and silver alloy. It is preferable.

[Surface coating layer]
Examples of various alloys constituting the surface coating layer include palladium-silver alloys as palladium alloys, rhodium-palladium alloys as rhodium alloys, ruthenium-iridium alloys as ruthenium alloys, platinum-gold alloys and iridium alloys as platinum alloys. Examples thereof include platinum-iridium alloys, gold alloys such as gold-silver alloys, and silver alloys such as silver-tin alloys. One type of surface film may be used, but two or more layers are preferable. As a typical layer configuration when the surface coating layer constituting the surface coating is two or more layers, Pd / Au, Rh / Au, Pd / Ag / Au, Pd are arranged in the order of lamination from the roughened coating 3 side. / Rh / Au, Ru / Pd / Au, and the like. By forming the surface film layer on the roughened film in this way, the heat resistance against heat generation of the lead frame is improved, and the strength of the projections of the roughened particles that form the roughened layer of the roughened film. Can be improved, the protrusions can be prevented from breaking, and an anchor effect can be exhibited. Further, from the viewpoint of improving the adhesion to the surface film, it is more preferable that the roughened layer is two layers of copper and nickel, and the surface film layer is two layers of Pd / Au or two layers of Rh / Au, As the layer structure of the roughened layer, the lower roughened layer is copper and the upper roughened layer is nickel, whereas the surface film layer is composed of Pd and the upper surface coated layer is Au. More preferably, the two layers 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 large, the surface irregularities of the roughened coating 3 may be buried, and the above-described effects of the present invention may not be sufficiently exhibited. The cost may increase. For this reason, it is preferable that the film thickness of each surface coating layer is 1 micrometer or less as a total film thickness (film thickness of a surface film) of the laminated | stacked surface coating layer, and it is more preferable that it is 0.03 or less.

(Lead frame material manufacturing method)
Next, the manufacturing method of the lead frame material 10 of the present invention will be described below.
A conductive substrate 1 is prepared, and a cathode electrolytic degreasing process and a pickling process are performed on the conductive substrate 1. Next, after forming an intermediate layer by electroplating, if necessary, a roughened film 3 including at least one roughened layer 2 is formed by electroplating, and then further electroplated as necessary. Thus, the lead frame material 10 can be manufactured by forming a surface film including at least one surface coating layer. As typical examples of production conditions, Table 1 shows cathode electrolytic degreasing conditions, Table 2 shows pickling conditions, Table 3 shows various intermediate layer forming conditions, Table 4 shows various roughening layer 2 forming conditions, 5 shows conditions for forming various surface coating layers. In the manufacturing method of the lead frame material 10 described above, the case where all of the intermediate layer, the roughening layer 2 and the surface coating layer are manufactured by electroplating is illustrated. The roughened layer 2 is preferably formed by an electroplating method because the shape of the protrusions can be controlled relatively easily by current density, stirring, temperature, treatment time, and the like, and is simple. The intermediate layer and the surface coating layer are also preferably formed by a wet plating method such as an electroplating method from the viewpoint of productivity, but may be manufactured by a dry plating method or other manufacturing methods, and there is a particular limitation. do not do.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these.
Various conductive substrates shown in Table 6 having a plate thickness of 0.2 mm that were cut in advance to a test piece size of 40 mm × 40 mm were prepared, and cathode electrolytic degreasing was performed under the conditions shown in Table 1 described 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 structure shown in Table 6 to prepare a test piece of lead frame material. Obtained. In addition, formation of the roughening layer controlled not only the specific surface area but also the ratio of the maximum width to the minimum width in the protrusion of the roughening layer in the cross section. Among Examples 1 to 30, for Examples 11 to 13, in addition to the lower roughened layer, the roughened film is further composed of two roughened layers by forming an upper roughened layer, In Examples 22 to 24, an intermediate layer is further formed between the conductive substrate and the roughened film. In Examples 29 and 30, the roughened film is added to the lower roughened layer. In addition, an upper roughened layer is formed to form two roughened layers, and a surface film including two layers of a lower surface covering layer and an upper surface covering layer is further formed. For reference, as Comparative Example 1, although the specific surface area of the roughened layer is as large as 550%, the ratio of the maximum width of the protrusions forming the roughened layer to the minimum width is not controlled, and is outside the scope of the present invention. A test piece of a lead frame material (5.2 times) was produced.

  In each of the above test pieces, a resin mold was injected using a transfer mold test apparatus (product name: Model FTS) manufactured by Kotaki Seiki Co., Ltd. under conditions of a mold temperature of 130 ° C., a holding time after molding of 90 seconds, and an injection pressure of 6.865 MPa. Molding was performed to form a pudding-like test piece having a contact area of 10 mm2. Each test piece was put into a high-temperature and high-humidity test (maintained at 85 ° C. and 85% RH for 168 hours), and the test piece was evaluated for the resin adhesion and the powder falling off under the following conditions. Table 7 shows the evaluation results.

(Resin adhesion evaluation)
Evaluation resin: G630L, manufactured by Sumitomo Bakelite Co., Ltd. (trade name)
Evaluation conditions: Apparatus: 4000 Plus, manufactured by Nordson Advanced Technology (trade name),
Load cell: 50kg
Measurement range: 10kg
Test speed: 100 μm / s
Test height: 10 μm

Table 7 shows the evaluation results of the resin adhesion. The evaluation of the resin adhesion shown in Table 7 is “A” when the shear strength (peel strength) is 9.8 MPa or more on the average and the shear strength (peel strength) is excellent. When the average is 4.9 MPa or more and less than 9.8 MPa, the resin adhesion is “B”, and when the shear strength (peel strength) is less than 4.9 MPa on the average, the resin adhesion is Shown as “C” as inferior.
The resin adhesion was evaluated by measuring both “initial shear strength” and “shear strength after high temperature and high humidity test”. The “shear strength after the high-temperature and high-humidity test” is a value after each test piece is resin-molded and left for 168 hours in an environment at a temperature of 85 ° C. and a humidity of 85%. The “initial shear strength” is the shear strength immediately after each test piece is resin-molded (before the high temperature and high humidity test).

(Evaluation of powder removal)
Powderiness was evaluated by visual evaluation. The evaluation results are shown in Table 7. In addition, the powder falling property shown in Table 7 is “A (excellent)” when powder falling from the surface is not recognized, “B (good)” when powder falling slightly occurs, A case where a great number of drops occur is indicated as “C (impossible)”, and “A” and “B” are levels for practical use.

  From the evaluation results of Table 7, in all of Examples 1 to 30, the initial shear strength and the shear strength after the high-temperature and high-humidity test are “A” or “B”, and good resin adhesion is maintained. In addition, the powder-off property was “A” or “B”, which was a practical level. On the other hand, although the specific surface area of the roughened layer is very large as 550%, the ratio of the maximum width of the protrusions forming the roughened layer to the minimum width is not controlled, and is outside the range of the present invention (5.2 times) In Comparative Example 1, the initial shear strength is “A” and the resin adhesion is excellent, but the shear strength after the high-temperature and high-humidity test is “C”, and the resin adhesion is greatly deteriorated. Furthermore, the powder-off property was inferior to “C”, and was not at a practical level.

  Even when the lead frame material of the present invention is subjected to a high temperature and high humidity durability test, for example, when a high temperature and high humidity test is performed under harsh conditions of leaving for 168 hours in an environment of a temperature of 85 ° C. and a humidity of 85%, Good resin adhesion to the lead frame can be maintained with almost no deterioration, and a semiconductor package constructed using this lead frame material can achieve high reliability.

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2 Roughening layer 2-1 1st roughening layer (1st roughening layer from a base-material side)
2-2 Second roughening layer (second roughening layer from the substrate side)
3, 3-1 Roughening film 4, 4-1 Protrusion 10, 10A Lead frame material A Cross-sectional line segment length of outermost surface of roughened film B Cross-sectional line segment length of surface of conductive substrate

Claims (4)

Tensile strength 350~800N / mm ^2, a conductivity of 30 to 90% IACS, a conductive substrate is thick 0.1~2mm der is, and a copper alloy,
A roughened film comprising at least one roughened layer formed of a plurality of roughened particle protrusions directly or via an intermediate layer on at least one surface of the conductive substrate;
The roughening layer is made of copper or nickel metal ,
The protrusion has a maximum width when measured in a cross section in the thickness direction of the roughened film, and a minimum width when measured at a lower portion located on the conductive substrate side than the measurement position of the maximum width. It has a shape that is 1 to 5 times the
The surface coating layer further includes a surface coating including at least one surface coating layer on at least a part of the surface of the roughened coating, and the surface coating layer includes palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, A lead frame material comprising a metal or alloy selected from the group of platinum, platinum alloys, iridium, iridium alloys, gold, gold alloys, silver and silver alloys. The lead frame material according to claim 1 , wherein the intermediate layer is nickel, nickel alloy, cobalt, cobalt alloy, copper, or copper alloy. Electricity is directly or via an intermediate layer on at least one surface of a conductive substrate having a tensile strength of 350 to 800 N / mm ² , a conductivity of 30 to 90% IACS, and a thickness of 0.1 to ² mm. Forming a roughened film including at least one roughened layer formed of protrusions of a plurality of roughened particles by plating,
The roughening layer is made of copper or nickel metal ,
The protrusion has a maximum width when measured in a cross section in the thickness direction of the roughened film, and a minimum width when measured at a lower portion located on the conductive substrate side than the measurement position of the maximum width. It has a shape that is 1 to 5 times the
The surface coating layer further includes a surface coating including at least one surface coating layer on at least a part of the surface of the roughened coating, and the surface coating layer includes palladium, palladium alloy, rhodium, rhodium alloy, ruthenium, ruthenium alloy, A method for producing a lead frame material comprising a metal or alloy selected from the group of platinum, platinum alloy, iridium, iridium alloy, gold, gold alloy, silver and silver alloy. A semiconductor package comprising the lead frame material according to claim 1 .

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