JP5089795B2 - Optical semiconductor device lead frame, optical semiconductor device lead frame manufacturing method, and optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead frame for an optical semiconductor device which is used in an LED, a photocoupler, a photointerrupter, or the like, that has its emission wavelength in a range from near-ultraviolet through visible light (wavelength 340-800 nm), and in which reflectivity is good when a chip emitting light in a near-ultraviolet range (wavelength 340-400 nm), especially a wavelength of around 375 nm, and in a visible light range (wavelength 400-800 nm), especially a wavelength of around 450 nm, is mounted and high luminance and excellent heat dissipation are ensured. <P>SOLUTION: The lead frame for an optical semiconductor device has a reflective layer partially or entirely at least on one side or both sides of the outermost surface of a substrate. On the outermost surface at least in a region where light emitted from an optical semiconductor element is reflected, the reflective layer has such a texture as a plating texture composed of silver or a silver alloy and deformed plastically. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an optical semiconductor device lead frame, a method for manufacturing the same, and an optical semiconductor device.

2. Description of the Related Art Lead frames for optical semiconductor devices are widely used as constituent members of various display / illumination light sources that use light emitting elements, which are optical semiconductor elements such as LED (Light Emitting Diode) elements, as light sources. In the optical semiconductor device, for example, a lead frame is arranged on a substrate, and after the light emitting element is mounted on the lead frame, the deterioration of the light emitting element and its peripheral parts due to external factors such as heat, moisture, and oxidation are prevented. The light emitting element and its periphery are sealed with resin, ceramic or the like.
In the case of an LED using a lead frame, a material such as a copper strip is formed into a punched shape by pressing or etching, and then plated with Ag, Au / Pd, or the like.

By the way, when the LED element is used as an illumination light source, the reflection material of the lead frame has a high reflectance in the entire visible light wavelength range (400 to 800 nm) (for example, the reflectance with respect to a reference material such as barium sulfate or aluminum oxide). 80% or more).
Furthermore, in recent years, the use of LEDs that emit ultraviolet rays (including near ultraviolet rays) has been expanded, such as light sources for measuring / analyzing instruments that use ultraviolet rays, photocatalytic air purifiers, ultraviolet sensors, and light sources for curing ultraviolet curable resins. In addition, optical semiconductor devices using LED elements have come to be used. The reflective material of this optical semiconductor device is required to have a high reflectance in the near ultraviolet region (wavelength 340 to 400 nm).
Furthermore, in the LED for illumination and backlight using white light, from the viewpoint of color rendering properties, instead of the conventionally used blue LED chip and yellow phosphor, purple / near ultraviolet / ultraviolet LED chip and RGB fluorescence are used. Techniques using the body (red, green, blue) have been developed. In this method, the reflecting material of the optical semiconductor device is required to have a high reflectance in the near ultraviolet region (wavelength 340 to 400 nm) and the visible light wavelength (400 to 800 nm).

  In addition, as a technique for realizing an LED that emits white light, a technique in which three chips emitting all colors of red (R), green (G), and blue (B) are arranged, a yellow phosphor on a blue LED chip, and so on. There are mainly three methods: a method using a sealing resin in which R is dispersed, and a method using a sealing resin in which R, G, and B phosphors are dispersed in an LED chip that emits wavelengths from the ultraviolet to the near ultraviolet region, respectively. Separated. Conventionally, a method using a sealing resin in which a yellow phosphor is dispersed in a blue chip has been the mainstream. However, this method has recently been changed to a light emission wavelength band from the viewpoint that the color rendering property of the red system is particularly insufficient. A technique using an LED chip including an ultraviolet region has attracted attention. For example, a technique in which an LED element having a wavelength of around 375 nm is used and RGB light is mixed with a sealing resin to emit white light has been studied.

  In response to such a demand, a layer (film) made of silver or a silver alloy is formed on the lead frame on which the LED element is mounted, particularly for the purpose of improving the light reflectance in the visible light region (hereinafter referred to as reflectance). ) Is often formed. It is known that the silver film has a high reflectance in the visible light region. Specifically, a silver plating layer is formed on the reflection surface (Patent Document 1), or 200 or after the silver or silver alloy film is formed. It is known that a heat treatment is performed at a temperature of not lower than 30 ° C. for 30 seconds or longer, and the crystal grain size of the film is 0.5 μm to 30 μm (Patent Document 2). Also, electrical contact materials for springs that have been heat-treated after rolling after silver plating are known, and the bonding strength between plated crystal grains is enhanced by rolling to improve wear resistance. Is known (Patent Document 3).

Japanese Patent Laid-Open No. 61-148883 JP 2008-016674 A Japanese Patent No. 3515226

  However, when only silver or an alloy film thereof is simply formed as in Patent Document 1, the decrease in the reflectance particularly in the near ultraviolet region (wavelength of 340 to 400 nm) is large, and it is short from about 400 nm in the visible light region. It was found that the reflectance reduction on the wavelength side (around 300 nm to 400 nm) is inevitable.

  Further, as in Patent Document 2, when the crystal grain size of the silver or silver alloy film is 0.5 μm to 30 μm on the surface of the base material having a surface roughness of 0.5 μm or more, the reflectance in the visible light region is good. There is an overall reflectivity improvement effect, but as seen in the conventional example of FIG. 8 and FIGS. 8 and 9 of Patent Document 2, the near ultraviolet region (340 to 400 nm), particularly 345 to 355 nm. An absorption peak is seen in the vicinity, and it can be seen that when an LED chip having an emission wavelength of 375 nm is used, it corresponds to a portion having a lower reflectance than the visible light region. At this time, it can be seen that the reflectance is about 10% lower than that when, for example, an LED chip with an emission wavelength of 375 nm is used, compared to a case where a blue LED chip with an emission wavelength of 450 nm is mounted. Although the appearance of this absorption peak is unknown in detail, it is difficult to improve the reflectance in the near ultraviolet region, particularly in the vicinity of 345 to 355 nm, simply by adjusting the crystal grain size. This result suggests that it contributes to improvement.

As a result of intensive studies, the present inventors have found that a crystal grain boundary formed by plating forms an absorption peak at the wavelength. Attempts were made to extinguish the absorption peak by reducing the crystal grain boundaries or by narrowing the gaps between the grain boundaries so that light is not absorbed.
In order to solve this problem, Patent Document 2 adopts a technique in which the crystal grain of silver plating is coarsened by a heat treatment after plating, the gap between the crystal grains is reduced, and as a result, the reflectance is increased. doing. However, even if the crystal grains are coarsened by heat treatment, for example, when considering a region where three or more crystal grains are close to each other, the gaps between the crystal grains are not necessarily completely eliminated or the gaps are narrowed. I can't do that. Therefore, when a product using such a heat-treated material is used, the base material or the base plating, which is the base material, is generated through the gap between the plated silver crystal grains due to the heat generated by the light emission of the light emitting element. It is thought that the layer is oxidized in contact with external air, and the oxidation of the plated silver is promoted to cause plating peeling. Further, if the crystal grains become coarser on the surface side, the roughness on the surface increases, and therefore it is conceivable that the reflectance is deteriorated by being affected by the larger surface roughness.
Further, there is a technique of using a leveler (leveling agent, smoothing agent) as plating for smoothing the surface. However, in order to smooth the plating surface without being affected by the surface roughness of the base material, a certain plating thickness is required. For example, on the surface of the base material having a surface roughness of 0.5 μm or more, When performing smooth plating, if the plating thickness is, for example, 10 μm or more, the surface roughness on the smooth plating surface can be obtained without being affected by the surface roughness of the base material. Since the plating thickness is increased as described above, it is considered that there is still room for improvement as a reflectance improvement means. In addition, when smoothing is performed using a leveling agent, the obtained surface cannot satisfy the reflectance, wire bondability, resin adhesion, etc. required for the lead frame. Improvement was needed.

  Further, Patent Document 3 has no knowledge about optical characteristics such as reflectance, and is not a rolling process for the purpose of improving reflectance. In addition, since low-temperature annealing (heat treatment) was performed to give the properties as a contact material after rolling, it was found that the substrate component diffused to the surface layer due to the heating and lowered the reflectivity. . This is because, in the case of normal electrical contact material applications, even if some surface diffusion occurs, the contact surface is maintained because the new surface is exposed by sliding and good conduction is obtained. When trying to develop the technology, the state of the outermost surface contributes most to the optical reflection phenomenon, so that the reflectivity is considered to decrease. From this, it can be seen that simply by rolling after plating and annealing, it cannot be easily developed for an optical semiconductor lead frame.

The luminous efficiency of the LED module is affected by the reflectance of the lead frame surface as well as the luminous efficiency of the LED chip. If the reflectivity of the lead frame surface is low, not only the light emission efficiency of the LED module is lowered, but also the heat generation on the lead frame surface is increased and the sealing resin is deteriorated. .
For this reason, when it is going to implement | achieve the LED module with high color rendering property using the LED chip which emits an ultraviolet light, the request | requirement of the reflectance improvement of the lead frame in the near ultraviolet region with a wavelength of 340-400 nm is very strong.

  Also, the emission wavelength of the optical semiconductor chip mounted on the white LED module is still mainly around 450 nm. For this reason, the improvement in the reflectance in the visible light region is very effective in improving the luminance of the LED module, and it is required to be as close as possible to the theoretical reflectance of the silver film (the reflectance is about 98% at 450 nm). However, there is still room for improvement.

  Therefore, the present invention provides an optical semiconductor device lead frame used in an LED, photocoupler, photointerrupter or the like whose emission wavelength includes the near ultraviolet to visible light range (wavelength 340 to 800 nm). 400 nm), particularly in the vicinity of a wavelength of 375 nm and in the visible light region (wavelength of 400 to 800 nm), particularly in the case of mounting a chip that emits light in the vicinity of a wavelength of 450 nm. An object is to provide a manufacturing method. Another object of the present invention is to provide an optical semiconductor device and an illumination device using the lead frame.

As a result of conducting sincerity studies in view of the above-described problems of the prior art, the present inventors have developed a lead frame for an optical semiconductor device in which a reflective layer made of silver or a silver alloy is formed on the outermost surface of a substrate by electroplating or the like. , as the reflective layer, by a plastically deformed metal structure smashed plating tissue by performing rolling at a predetermined working ratio after plating layer formed, extinguish unwanted absorption peak near wavelengths 345nm~355nm It has been found that a lead frame for a semiconductor device can be obtained that can be remarkably suppressed and is excellent in the reflectance of light in the near ultraviolet region having a wavelength of 340 to 400 nm. In addition, the reflectance in the visible light region can be improved by several percent compared to the conventional silver plating film, and for semiconductor devices with excellent light reflectance by being close to the theoretical value of silver. The inventors have found that a lead frame can be obtained, and have reached the present invention based on this finding.

That is, the said subject is solved by the following means.
(1) An optical semiconductor device lead frame comprising a reflective layer on at least one surface or both surfaces of the outermost surface of the substrate, and a part or the entire surface of the substrate, wherein the reflective layer reflects at least light of the optical semiconductor element. in the outermost surface of the reflective region, the entire organization has a plastically deformed silver or silver alloy plating tissues, the processing rate by the rolling of the of the plating tissue than 60% or more 37% by rolling, the reflective layer The thickness after plastic deformation is 0.2 to 10 μm, the reflectance of light having a wavelength of 340 nm is 60% or more, the reflectance of light having a wavelength of 375 nm is 75% or more, and the reflectance of light having a wavelength of 400 nm is 80%. % Or more, the reflectance of light of wavelength 450 nm and wavelength 600 nm is 90% or more, respectively, and the reflectance of light of wavelength 375 nm is larger than the reflectance of light of wavelength 340 nm. Wherein the lead frame for an optical semiconductor device.
(2) The lead frame for an optical semiconductor device according to (1), wherein the reflective layer is provided on the base via at least one metal layer and is heat resistant. .
( 3 ) The silver or silver alloy forming the reflective layer is silver, silver-tin alloy, silver-indium alloy, silver-rhodium alloy, silver-ruthenium alloy, silver-gold alloy, silver-palladium alloy, silver-nickel. The lead frame for optical semiconductor devices according to (1) or (2) , which is an alloy, a silver-selenium alloy, a silver-antimony alloy, or a silver-platinum alloy.
( 4 ) The lead for an optical semiconductor device according to any one of (1) to ( 3 ), wherein the base is made of copper, copper alloy, iron, iron alloy, aluminum, or aluminum alloy. flame.
( 5 ) A plating layer made of any one of silver, silver alloy, tin, tin alloy, gold, or gold alloy is provided at least in a portion requiring soldering, (1) to ( 4 ) The lead frame for optical semiconductor devices according to any one of the above.
( 6 ) A method of manufacturing a material for a lead frame for a semiconductor device according to any one of (1) to ( 4 ), wherein at least light emitted from an optical semiconductor element is reflected on the outermost surface of the substrate. A reflective layer made of silver or a silver alloy is formed in the reflective region by electroplating, electroless plating or sputtering, and then subjected to rolling to plastically deform the plated structure. The manufacturing method of the lead frame material for optical semiconductor devices characterized by making the processing rate of 37 to 60%.
( 7 ) A method of manufacturing a lead frame for a semiconductor device according to any one of (1) to ( 4 ), wherein the reflective region is an outermost surface of the substrate and reflects at least light emitted from the optical semiconductor element. After forming a reflective layer made of silver or a silver alloy by electroplating, electroless plating, or sputtering, a rolling process is performed to obtain a lead frame material for an optical semiconductor device in which the plating structure is plastically deformed, An optical semiconductor device characterized in that the material is punched by a pressing method or an etching method to obtain a lead frame, and the processing rate of the rolling of the plated structure is 37% or more and 60% or less. Of manufacturing leadframes for use in a car.
( 8 ) The method of manufacturing a lead frame for an optical semiconductor device according to the item ( 7 ), wherein plating with good solderability is partially performed after the punching process.
( 9 ) The plating with good solderability is applied to at least a region other than the region that reflects the light emitted from the optical semiconductor element, and the component of the plating is silver, silver alloy, tin, tin alloy, gold, or The method for producing a lead frame for an optical semiconductor device according to item ( 8 ), wherein the method is any one of gold alloys.
( 10 ) An optical semiconductor device comprising an optical semiconductor element and the lead frame for an optical semiconductor device according to any one of (1) to ( 5 ), wherein the optical semiconductor device lead frame includes: An optical semiconductor device characterized in that the reflective layer is provided on the outermost surface of the substrate and at least in a region that reflects light generated from the optical semiconductor element, and the plating structure has a plastically deformed structure.
(11), wherein the emission wavelength of the optical semiconductor element is to 800nm 340 nm, (10) The optical semiconductor device according to claim.
( 12 ) The optical semiconductor device according to ( 10 ) or ( 11 ), wherein the light output from the device is white light.
( 13 ) The optical semiconductor device according to ( 10 ) or ( 11 ), wherein the light output from the device is ultraviolet, near ultraviolet, or violet light.
( 14 ) An illumination device comprising the optical semiconductor device according to any one of ( 10 ) to ( 13 ).

According to the present invention, after a reflective layer made of silver or a silver alloy is formed on the outermost surface of the substrate by electroplating, electroless plating, or sputtering, the reflective layer is further rolled at a predetermined processing rate. by producing plastic deformation applied is in the plating tissue, unwanted absorption peak near wavelengths 345nm~355nm described above can be either or significantly suppressed extinguish, especially in the working rate during rolling process 37% By setting it as the above, the reflectance in 340-400 nm which is a near ultraviolet region is improved, and a favorable reflectance is especially obtained in the optical semiconductor device mounted with the optical semiconductor chip which includes the wavelength of the near ultraviolet region in the emission wavelength. Furthermore, the reflectance can be improved to the theoretical value level of the silver film by using the same method, and the reflectance at a wavelength of 400 to 800 nm which is a visible light region can be improved. Good reflectivity can be obtained in an optical semiconductor device. That is, according to the present invention, a light-emitting chip having a good reflection characteristic over a wide range from the near ultraviolet light to the visible light region, particularly a wavelength of 340 to 400 nm, and further, a visible light region of 400 to 800 nm is combined. When used, it is possible to provide a lead frame for an optical semiconductor device which is superior in reflection characteristics than a conventional silver plating material. Further, by using this optical semiconductor device lead frame, a high-intensity optical semiconductor device and illumination device can be provided.

1 is a schematic cross-sectional view of a first embodiment of a lead frame for an optical semiconductor device according to the present invention. It is a schematic sectional drawing of 2nd Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is a schematic sectional drawing of 3rd Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is a schematic sectional drawing of 4th Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is a schematic sectional drawing of 5th Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is a schematic sectional drawing of 6th Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is a schematic sectional drawing of 7th Embodiment of the lead frame for optical semiconductor devices which concerns on this invention. It is the graph which showed the reflectance of the lead frame for optical semiconductor devices of the invention example 19 based on this invention with the reflectance of the prior art example 1. FIG.

In the lead frame of the present invention, a silver or silver alloy layer as a reflective layer is initially formed by electroplating, electroless plating or sputtering, and the layer is subjected to rolling to provide electroplating or non-electroplating. A metal structure (plating structure) formed by electrolytic plating or sputtering has a reflective layer in which plastic deformation has occurred. By forming a reflective layer in which the plating layer is plastically deformed, unnecessary absorption peaks in the vicinity of a wavelength of 345 nm to 355 nm can be eliminated or remarkably suppressed, and the reflectance can be improved. It is suitably used for an optical semiconductor device on which a light emitting chip having an emission wavelength of about 375 nm is mounted. At the same time, even in the visible light wavelength region of 400 nm to 800 nm, the reflectance can be increased to the theoretical value of Ag.
The plating method may be a wet plating method such as an electroplating method or an electroless plating method, or a dry plating method such as a sputtering method.
In addition, according to the rolling process, the entire material including the substrate is subjected to the rolling process, so that the entire plating structure is subjected to plastic deformation.

The present invention is characterized in that the outermost surface has a reflective layer plastically deformed by rolling with respect to a metal structure (plating structure) formed by an electroplating method, an electroless plating method or a sputtering method. Here, the plastically deformed metal structure is different from the cast structure as is metallurgically clear in the present technical field, and is also different from the plated structure before deformation formed by plating. Specifically, fine crystals are usually seen on the surface after plating, and a needle-like structure, a precipitation state of spherical particles, etc. are seen, while the surface state after rolling after plating is the roll of a roll. Since the processed pattern formed on the eye has a surface property that is transferred to the lead frame side, the surface is observed with a general-purpose SEM at an observation magnification of 2000 to 10,000 times. Is possible.

Furthermore, according to the lead frame of the present invention, not only the wavelength range of 340 to 400 nm but also the wavelength range of 400 to 800 nm which is the visible light range can reach the physical theoretical value of the reflectance of silver as much as possible. This is because the reflectivity is about 98% at a wavelength of 450 nm when pure silver is formed on a mirror substrate such as silicon by sputtering. However, it is easy to use a brightener by simply plating. It is a numerical value that cannot be achieved. The inventors have made a plastic deformation in the plated structure by rolling after plating, reduced fine irregularities by crushing the plated structure, and reduced / eliminated the crystal grain boundaries. As a result, it was clarified that the reflectance can be brought close to the theoretical value even in the visible light region. As a result, by using the lead frame according to the present invention, excellent luminance can be obtained even in a conventional optical semiconductor device in the visible light range, and a blue light emitting element having a wavelength range of 400 to 800 nm, particularly a light emission wavelength of around 450 nm is mounted. It is suitably used for an optical semiconductor device.

  In the present invention, the reflection layer made of silver or a silver alloy may be formed on the outermost surface of at least a portion that contributes to light reflection (that is, a region that reflects at least light emitted from the optical semiconductor element). In other portions, it is not necessary to provide a reflective layer, and even if a layer other than the reflective layer is formed, there is no particular problem in terms of reflectance.

The production method according to the present invention will be described in detail. A part or all of both or one side of a conductive substrate (for example, a strip) is subjected to electroplating, electroless plating, or sputtering to produce silver or silver A reflective layer made of an alloy is formed and subjected to plastic working by rolling. Next, the shape of the lead frame is formed by pressing or etching.
A chip mounting portion is formed on the lead frame by a resin mold or the like, and an optical semiconductor module is manufactured by mounting an optical semiconductor chip, wire bonding, and sealing with resin or glass containing a phosphor.
In the conventional method, generally, after a conductive base (such as a strip) is formed into a lead frame shape by pressing or etching, silver plating or gold / palladium / nickel plating is performed. Moreover, in the method of the said patent document 2, it attaches to predetermined heat processing after metal plating, and makes the particle size of a plating layer coarse.
The present invention and the conventional method are the ones in which the present invention is a modification of the plating structure as a mechanical processing finish, whereas the conventional method is a simple processing finish by cladding, plating finish or heat treatment finish, or The structure is completely different in that the heat treatment for plating and rolling is improved.

The processing rate at the time of rolling process (or reduction ratio) be 37% or more in a portion at a point is used as the reflective layer. The higher the processing rate, the better the reflection characteristics and the higher the brightness of the LED lead frame. The processing rate at the time of rolling after reflection layer formed is not only the effect of the reflection characteristic improvement exceeds 60% is saturated, since cracks and cracks during bending easily occurs, and 60% or less .
“Processing rate” indicates a ratio represented by “(plate thickness before processing−plate thickness after processing) × 100 / (plate thickness before processing)”. In addition, “location used as a reflective layer” means that when an optical semiconductor module is formed, an optical semiconductor module is obtained by resin-molding a portion other than the light emitting portion, but the optical semiconductor chip emits light. In this case, it means a portion where the lead frame is exposed and a portion where light reflection occurs.

  The lead frame for an optical semiconductor device of the present invention has good reflectance characteristics and can easily form a film by using copper or a copper alloy, iron or an iron alloy, or aluminum or an aluminum alloy as a base. A lead frame that can contribute to cost reduction can be provided. In addition, the lead frame based on these metals or alloys has excellent heat dissipation characteristics, and the heat energy generated when the light emitter emits light can be smoothly discharged to the outside through the lead frame, and light emission It is expected that the lifetime of the element will be prolonged and the reflectance characteristics will be stabilized over a long period of time. This depends on the conductivity of the substrate, preferably at least 10% by IACS (International Annealed Copper Standard), more preferably 50% or more.

In addition, the lead frame for an optical semiconductor device of the present invention stably increases the reflectivity by setting the thickness of the reflective layer after plastic working such as rolling made of silver or a silver alloy to 0.2 μm or more. In addition, it is possible to suppress deterioration due to heating in a subsequent process such as wire bonding or sealing with resin or glass. The thickness of the upper limit of the reflecting layer after the plastic working of the rolling process or the like, from the viewpoint of silver reduction and plating costs noble metals shall be a 10μm or less. When it is thinner than the lower limit (for example, 0.1 μm), discoloration due to heating occurs and the rate of improvement in reflectance is small. For this reason, in order to prevent discoloration due to heating more stably, the thickness of the reflective layer after plastic working such as rolling is preferably 0.5 μm or more.

  Further, the silver or silver alloy forming the reflective layer in the lead frame for optical semiconductor devices of the present invention is silver, silver-tin alloy, silver-indium alloy, silver-rhodium alloy, silver-ruthenium alloy, silver-gold alloy, A lead frame having good reflectivity and good productivity is made of a material selected from the group consisting of silver-palladium alloy, silver-nickel alloy, silver-selenium alloy, silver-antimony alloy, and silver-platinum alloy. In particular, silver, a silver-tin alloy, a silver-indium alloy, a silver-palladium alloy, a silver-selenium alloy, or a silver-antimony alloy is more preferable from the viewpoint of improving the reflectance.

  The lead frame for an optical semiconductor device of the present invention is selected from the group consisting of nickel, nickel alloy, cobalt, cobalt alloy, copper, and copper alloy between the base and the reflective layer made of silver or silver alloy. An intermediate layer made of a metal or an alloy may be provided. The intermediate layer is suitably formed by plating, for example.

For example, when an iron-based substrate is used, the thermal conductivity of the material is relatively low. Therefore, by providing a copper or copper alloy layer as an intermediate layer, the heat dissipation can be improved without impairing the reflectance. Furthermore, since the plating layer which is the copper or copper alloy layer contributes to the improvement of plating adhesion, it is possible to prevent deterioration of adhesion due to heat generation when the light emitting element emits light.
In the case of using a copper or copper alloy substrate, a nickel, nickel alloy, cobalt, or cobalt alloy layer is used as an intermediate layer in order to suppress diffusion of the substrate component to the reflective layer due to heat generated when the light emitting element emits light. It is effective to provide it.

In addition, for the purpose of preventing sulfur gas and moisture in the outside air that permeates the sealing resin, the improvement of the resin is also progressing, and in some cases, glass sealing is being performed, and during the sealing process with resin or glass The processing temperature is also rising. For example, when incorporated in an optical semiconductor device such as an LED, the diffusion phenomenon is expected to proceed due to heat generated by the LED chip. In order to suppress diffusion during use in such a process or as an apparatus, it is effective to provide an intermediate layer.
The thickness of these intermediate layers is not particularly limited in the present invention, but is preferably in the range of 0.08 to 2.0 μm.

Moreover, the working ratio during rolling process, by preparing a reflective layer initial formation immediately (plating immediately after) of the plate for an optical semiconductor material for lead frames as 37% or more as a processing rate based on the thickness (strip material), the plastic A layer composed of deformed silver and a silver alloy can be obtained, and a decrease in reflectivity due to the appearance of a reflectivity absorption peak at 340 to 400 nm can be prevented, and even at a wavelength of 400 to 800 nm, which is a visible light region, can be obtained by plating. A lead frame having a reflectance improved by several percent over the obtained silver or silver alloy film can be obtained. In addition, when the processing rate at the time of the rolling process after formation of a reflective layer is less than 1%, plastic deformation is inadequate and the effect is few.

Next, the rolling process will be described.
There may be any number of rolling steps from the thickness immediately after the initial reflective layer formation (immediately after plating) to the product thickness of the lead frame for optical semiconductors. However, productivity increases as the number of rolling increases. The number of rolling is preferably at most 3 times. The processing rate at the time of rolling after the reflective layer is formed may be 37 % or more in each rolling. On the other hand, as the total processing rate from the thickness immediately after the initial formation of the reflective layer (immediately after plating) to the product thickness, the reflectance can be further improved and stabilized, the change in mechanical properties of the substrate is suppressed, and In consideration of the fact that the plating structure of the reflective layer can be uniformly rolled, the processing rate during the rolling process after forming the reflective layer is set to 37 % or more in total.

If the processing rate at the time of rolling after forming the reflective layer is too large, the plating thickness increases at the time of initial formation of the reflective layer (during plating), resulting in not only an increase in plating cost but also an environmental load. In addition, since the processing cost increases due to the increase in the number of rolling processes after the reflective layer is formed and the effect of improving the reflectance is saturated, the reflective layer is formed because the cracks and cracks are likely to occur during bending. working ratio during rolling of the latter shall be the 60% or less in total.
In addition, when the optical semiconductor device that is the step of applying a bending after mounting the optical semiconductor chip, consider bending workability and the processing rate to 37 to 60% in total.

Furthermore, in order to control the mechanical properties required, the rolling machining (also referred to as temper or low-temperature annealing) Batch type or thermal treatment by a technique such as an inter-running type after that the applied, as well as refining, grain boundaries The grain boundary spacing can be narrowed by strengthening the bonding force between the crystal grains, but it is necessary to keep the heat treatment to such an extent that the reflectance is not lowered.
The conditions of the heat treatment to be applied after such rolling machining, but are not particularly limited, for example, at a temperature 50 to 150 ° C., it is preferable to perform the heat treatment of 0.08 - 3 hours. If the temperature of this heat treatment is too high or the time is too long, the heat history becomes excessive and the reflectance is lowered.

As described above, the reflective layer on the surface made of silver or a silver alloy may be formed by wet plating using an electroplating method or an electroless plating method, or may be plated on the surface of the metal substrate by a sputtering method. It may be formed by applying and precipitating. Here, the electroplating method is described as a representative example, but in the case of the electroless plating method and the sputtering method, a layer made of silver or a silver alloy is used in the same manner as in the case of the electroplating method. Can be formed. For example, in the case of the electroless plating method, it may be formed by using a commercially available bath (for example, S.D. Ag40; manufactured by Sasaki Chemical Co., Ltd.) or the like. Can be used.
The thickness of the reflective layer made of silver or a silver alloy after the rolling process is not particularly limited, but is preferably in the range of 0.5 to 10 μm. The coating thickness (initial thickness) before processing for achieving the thickness after rolling is not particularly limited, but is preferably in the range of 1 to 50 μm, for example.
Rolling to a material in which a part or all of the conductive substrate is coated with silver or a silver alloy is performed, for example, by rolling with a cold rolling mill. The rolling machine includes a 2-stage roll, a 4-stage roll, a 6-stage roll, a 12-stage roll, a 20-stage roll, and the like, and any rolling machine can be used.
The processing rate (area reduction) in the rolling process is 37 % or more, and the gap between the grain boundaries of silver or silver alloy can be sufficiently narrowed to form a plastic deformation structure.
The rolling roll used for the rolling process is preferably less than 0.1 μm in terms of the arithmetic average (Ra) of the surface roughness in consideration of improving the reflectance on the lead frame side formed by transferring the rolls.

The optical semiconductor device of the present invention is provided with a layer made of silver or a silver alloy at least at a location where light generated from the optical semiconductor element is reflected, and has a layer that is plastically deformed by rolling as a reflective layer. By using the lead frame of the present invention, the reflectance characteristics can be obtained effectively at low cost. This is because the reflectance characteristics are sufficiently effective by forming a reflective layer made of silver or a silver alloy only on the mounting portion of the optical semiconductor element. When the LED mounting surface is only one side of the lead frame, the optical semiconductor element mounting surface of the double-sided plating material may be thickened and the non-mounting surface may be thinned.

Furthermore, the reflective layer made of silver or a silver alloy may be partially formed, one-side plating or stripe plating, formed by partial plating, such as spot plating, may be more formed thereafter rolling machining . Manufacturing a lead frame in which the reflective layer is partially formed can reduce the amount of metal used in the part where the reflective layer is unnecessary, so that a lead frame with a low environmental load can be obtained. Fewer optical semiconductor devices can be obtained.

Incidentally, with respect to soldering the external lead after optical semiconductor module formed, it was subjected to rolling machining to form a reflective layer after plating a metal or an alloy such as silver or silver alloy on both sides material (strip material) In this case, since the punching process or the etching process is performed thereafter to form a predetermined lead frame shape, the substrate is necessarily exposed at the end face of the lead frame obtained. If the lead frame after pressing or etching is stored with the substrate exposed, there is a concern about corrosion of the substrate component or deterioration of solderability to the surface of the substrate.
For example, when silver or a silver alloy is coated on both surfaces of the substrate, the exposed area of the substrate is very small with respect to the entire surface, and there is almost no effect on the solderability with external leads. Further, the exposure of the substrate does not cause a problem even in the case of a thin plate thickness or a wide lead width. However, in the case of a thick plate thickness or a narrow lead width, soldering with a lead may affect the soldering, and the reliability of soldering is enhanced when the external lead is plated.
Furthermore, when only one side of the substrate is coated with a metal such as silver or a silver alloy or an alloy thereof, or when performing partial plating including an optical semiconductor element mounting portion (for example, spot-shaped or stripe-shaped plating), external leads Since the exposed area of the substrate at the part is large, it is preferable to provide a plating film with good solder wetting after pressing or etching.

To plated external lead, silver or a silver alloy of a metal or a material forming the reflecting layer is subjected to a rolling machining after plating the alloy (strip member) After pressing, the reflection area of the lead frame Otherwise, solder wetting is improved by providing a plating film (soldering improvement layer) with good solder wetting such as silver, tin, gold, or an alloy thereof at least on the external lead portion to be soldered. Similarly, when the heating temperature is high in the process after chip mounting, the plating after pressing is effective from the viewpoint of solderability of the external leads.
In plating after pressing or etching, it is sufficient to mask and plating at least a region including a portion corresponding to the reflection region of light emitted from the optical semiconductor element, and any method such as a tape, a resist mask, a drum mask, or a belt mask is used. be able to. Moreover, you may perform exterior plating after formation of the module (resin mold) normally used by IC semiconductor.
The thickness of the plating film having good solder wettability to the external lead is not particularly defined in the present invention, but it is sufficient that the solderability and the corrosion resistance during storage are ensured, and is about 0.1 μm. That's all you need. Similarly, the plating type may be a metal type that achieves the purpose, such as silver, tin, gold, or alloy plating thereof.

Embodiments of a lead frame for optical semiconductor devices according to the present invention will be described below with reference to the drawings. In each of the drawings, there is a case where an optical semiconductor element is mounted on a lead frame. Each embodiment is merely an example, and the scope of the present invention is not limited to each embodiment.
In addition, the illustrated form is omitted to the extent necessary for the description, and the dimensions and the specific lead frame or element structure are not construed as being limited to the illustrated one.

FIG. 1 is a schematic cross-sectional view of a first embodiment of a lead frame for an optical semiconductor device according to the present invention. In the lead frame of this embodiment, a reflective layer 2 made of silver or a silver alloy is formed on a base 1, and an optical semiconductor element 3 is mounted on a part of the surface of the reflective layer 2. Further, the other lead frame insulated by the broken wire 9 (abbreviated as a broken line-shaped region in the figure) and the optical semiconductor element 3 are electrically connected by the bonding wire 7 to form a circuit. Is formed. In the present invention, in the lead frame of the present embodiment, after the reflective layer 2 is formed by electroplating, for example, plastic deformation is caused by rolling, and reflection in the near ultraviolet region and the visible light region (wavelength 340 nm to 800 nm). This leads to an optical semiconductor device lead frame having excellent characteristics.

  FIG. 2 is a schematic sectional view of a second embodiment of the lead frame for an optical semiconductor device according to the present invention. The lead frame of the embodiment shown in FIG. 2 is different from the lead frame shown in FIG. 1 in that an intermediate layer 4 is formed between the base 1 and the reflective layer 2. Other points are the same as those of the lead frame shown in FIG.

3 and 4 is an schematic cross-sectional view of the third and fourth embodiments rolled machining after only, for example electroplating one side of a side where the optical semiconductor element is mounted is disposed a reflective layer 2 which has been subjected 3 and FIG. 4 is the presence or absence of the intermediate layer 4.

FIG. 5 is a schematic sectional view of a fifth embodiment of a lead frame for an optical semiconductor device according to the present invention. FIG. 5 shows a state in which the optical semiconductor module is formed by the mold resin 5 and the sealing resin 6 for convenience, and a part where the optical semiconductor element 3 is mounted and a part that causes a reflection phenomenon in the vicinity thereof. And the reflective layer 2 is formed only inside the mold resin 5. In the present embodiment, the intermediate layer 4 is formed on the entire surface of the substrate 1, but may be partially formed as long as it is interposed between the substrate 1 and the reflective layer 2. Further, the reflective layer 2 is formed halfway down the mold resin 5, but it is sufficient that the region that is a part contributing to the reflection phenomenon is covered, and only the outside of the mold resin 5 or the inside of the mold resin is covered. It may be in a state of being broken.
In the present invention, it is also possible to form the reflective layer 2 made of silver or a silver alloy only in a portion that contributes to light reflection.

  FIG. 6 is a schematic sectional view of a sixth embodiment of a lead frame for an optical semiconductor device according to the present invention. FIG. 6 shows, for convenience, that the optical semiconductor module is formed of the mold resin 5 and the sealing resin 6 as in FIG. The embodiment of FIG. 6 differs from FIG. 5 in that the intermediate layer 4 is provided only on the surface of the substrate 1 on which the optical semiconductor element 3 is disposed, and the reflective layer 2 is provided on the entire surface of the substrate 1. It is that you are.

FIG. 7 is a schematic sectional view of a seventh embodiment of the lead frame for an optical semiconductor device according to the present invention. In FIG. 7, the soldering improvement layer 7 made of plating with good solderability (silver or silver alloy plating, tin or tin alloy, gold or gold alloy) is provided on the press end surface and back surface at the external soldering equivalent part. Has been given. In FIG. 7, the optical semiconductor element (3) mounted on the lead frame is not shown.
More stable solderability can be ensured by the soldering improvement layer 7 made of, for example, silver, tin, gold or the like provided after the pressing. In this case, the surface on which the reflective layer (2) is formed, and solderability is applied to a portion other than a portion where reflectance is required (that is, at least a region that reflects light emitted from the optical semiconductor element). The improvement layer 7 may be provided.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this.

Example 1
As Example 1, the substrate having a width of 100 mm shown in Table 1 was subjected to the following pretreatment and then subjected to the following electroplating treatment. In order to make the total plate thickness including the coating thickness after rolling 0.2 mm, the plate thickness at the initial formation of the reflective layer (during plating) is changed in consideration of the processing rate at the time of rolling after forming the reflective layer. The reflective layer was initially formed by plating. Thereafter, using a 6-high rolling mill (manufactured by Hitachi, Ltd.), using a roll having a surface roughness Ra of approximately 0.03 μm, the rolling work roll is rolled to a thickness of 0.2 mm according to the area reduction ratio shown in Table 1. As a result, samples of Invention Examples 1 to 14, 19, and 22 to 38 and Reference Examples 1 to 3 having the configurations shown in Table 1 were obtained (rolled products). Reference Example 4 imitates Comparative Example 1 of Patent Document 3 and Reference Example 5 imitates Example 2 of Patent Document 3, and after the rolling process, heat treatment is performed at 240 ° C. for 4 hours. Prepared what was carried out (finished product after heat treatment). Moreover, about the prior art examples 1-4, after performing the pre-processing shown below to the base | plate thickness of 0.2 mm and width | variety of 100 mm, by performing the electroplating process for forming the reflective layer shown below, The base material (strip material) for lead frames shown in Table 1 was produced. (Conventional Examples 1, 2, and 4 are plated products.) Regarding Conventional Example 3, in order to reproduce the coating state described in Example 8 of Patent Document 2 described above on the substrate in this example, After forming the plating layer under the conditions described in Document 2, a heat treatment was performed at 320 ° C. for 30 seconds in an atmosphere with a residual oxygen concentration of 500 ppm (finished product after heat treatment). The inventive example without the intermediate layer and the comparative example correspond to the structure of the lead frame shown in FIG. 1, and the inventive example with the intermediate layer and the reference example correspond to the structure of the lead frame shown in FIG.
In the evaluation of this example, for the sake of simplicity, the press work was not performed, and the evaluation was performed using a strip shape.

Among the materials used as the substrate, “C14410 (Cu-0.15Sn: EFTEC-3 manufactured by Furukawa Electric Co., Ltd.)”, “C19400 (Cu—Fe-based alloy material: Cu-2.3Fe-0.03P) -0.15Zn) "," C26000 (brass: Cu-30Zn) "," C52100 (phosphor bronze: Cu-8Sn-P) "," C77000 (Western white: Cu-18Ni-27Zn) ", and" C18045 ( "Cu-0.3Cr-0.25Sn-0.5Zn: EFTEC-64T manufactured by Furukawa Electric Co., Ltd." represents a copper or copper alloy substrate, and the alloy number indicates the type according to the CDA (Copper Development Association) standard. . In addition, the unit of the number before each element is mass%.
Further, “A1100”, “A2014”, “A3003”, and “A5052” represent aluminum or aluminum alloy substrates, each of which is specified in Japanese Industrial Standards (JIS H 4000: 2006, etc.).
“42 Alloy” represents an iron-based substrate, containing 42% by mass of nickel, and the balance of iron and inevitable impurities.
In addition, when the substrate was aluminum, it was subjected to a process of electrolytic degreasing, pickling and zinc replacement treatment, and in the case of other substrates, a pretreatment was performed through the steps of electrolytic degreasing and pickling. Moreover, before each silver or silver alloy plating, silver strike plating was performed, and the outermost layer plating thickness was expressed as the thickness after rolling including the silver strike plating thickness.

The pretreatment conditions in Example 1 are shown below.
(Pretreatment conditions)
[Cathode electrolytic degreasing]
Degreasing solution: NaOH 60 g / liter Degreasing conditions: 2.5 A / dm ² , temperature 60 ° C., degreasing time 60 seconds [pickling]
Pickling solution: 10% sulfuric acid pickling condition: 30 seconds immersion, room temperature [zinc substitution] (used when the substrate is aluminum)
Zinc replacement solution: NaOH 500 g / liter, ZnO 100 g / liter, tartaric acid (C ₄ H ₆ O ₆ ) 10 g / liter, FeCl _{2 2} g / liter Treatment conditions: 30 seconds immersion, room temperature [Ag strike plating] coating thickness 0.01 μm
Plating solution: KAg (CN) ₂ 5 g / liter, KCN 60 g / liter,
Plating conditions: current density 2 A / dm ² , plating time 4 seconds, temperature 25 ° C.

The liquid composition and plating conditions of the intermediate layer plating used in Example 1 are shown below.
(Interlayer plating conditions)
[Ni plating]
Plating _{solution: Ni (SO 3 NH 2)} 2 · 4H 2 O 500g / l, NiCl ₂ 30 g / _l, H ₃ BO ₃ 30g / l Plating Conditions: current density 5A / dm ^2, temperature 50 ° C.
[Co plating]
Plating _{solution: Co (SO 3 NH 2)} 2 · 4H 2 O 500g / l, CoCl ₂ 30 g / _l, H ₃ BO ₃ 30g / l Plating Conditions: current density 5A / dm ^2, temperature 50 ° C.
[Cu plating]
Plating solution: CuSO ₄ .5H ₂ O 250 g / liter, H ₂ SO ₄ 50 g / liter, NaCl 0.1 g / liter Plating condition: current density 6 A / dm ² , temperature 40 ° C.

The liquid composition and plating conditions for the reflective layer plating used in Example 1 are shown below.
(Reflective layer plating conditions)
[Ag plating]
Plating solution: AgCN 50 g / liter, KCN 100 g / liter, K ₂ CO ₃ 30 g / liter Plating condition: current density 1 A / dm ² , temperature 30 ° C.
[Ag-Sn alloy plating]
Plating solution: KCN 100 g / liter, NaOH 50 g / liter, AgCN 10 g / liter, K ₂ Sn (OH) ₆ 80 g / liter Plating condition: current density 1 A / dm ² , temperature 40 ° C.
[Ag-In alloy plating]
Plating solution: KCN 100 g / liter, NaOH 50 g / liter, AgCN 10 g / liter, InCl ₃ 20 g / liter Plating condition: current density 2 A / dm ² , temperature 30 ° C.
[Ag-Pd alloy plating]
Plating solution: KAg [CN] ₂ 20 g / liter, PdCl ₂ 25 g / liter, K ₄ O ₇ P ₂ 60 g / liter, KSCN 150 g / liter Plating condition: current density 0.5 A / dm ² , temperature 40 ° C.
[Ag-Se alloy plating]
Plating solution: KCN 150 g / liter, K ₂ CO ₃ 15 g / liter, KAg [CN] ₂ 75 g / liter, Na ₂ O ₃ Se5H ₂ O 5 g / liter Plating condition: current density 2 A / dm ² , temperature 50 ° C.
[Ag-Sb alloy plating]
Plating solution: KCN 150 g / liter, K ₂ CO ₃ 15 g / liter, KAg [CN] ₂ 75 g / liter, C ₄ H ₄ KOSb 10 g / liter Plating conditions: current density 1 A / dm ² , temperature 50 ° C.

(Evaluation method)
The lead frames of the invention examples, reference examples, and conventional examples obtained as described above were evaluated according to the following tests and standards. The results are shown in Table 2.
(1A) Reflectance measurement: In a spectrophotometer (U-4100 (trade name, manufactured by Hitachi High-Technologies Corporation)), continuous measurement was performed with a total reflectance of 300 nm to 800 nm. Among these, Table 2 shows the total reflectance (%) in the ultraviolet region to the near ultraviolet region of 340 nm, 375 nm, and 400 nm, and further in the visible light region of 450 nm and 600 nm. It is required that the reflectance at a wavelength of 340 nm is 60% or more, the reflectance at 375 nm is 75% or more, the reflectance at 400 nm is 80% or more, and 90% or more at wavelengths of 450 nm and 600 nm in the visible light region. Characteristic.
(1B) Heat resistance: The state of discoloration was visually observed after heat treatment in air at 150 ° C. and 190 ° C. for 3 hours. If there is no discoloration, it will be judged as “good”, and “○” will be attached to the table. If it is slightly brown, it will be judged as “possible”, and “△” will appear on the table. Judgment was “impossible” and “x” was added to the table, and “possible” or higher was regarded as a practical level.
(1C) Bending workability: 90 ° bending was performed in a direction parallel to the rolling bar at a bending radius of 0.2 mm using a 1-ton press. The apex of the bent portion was observed with a stereomicroscope at a magnification of 100 to investigate the presence or absence of cracks. A sample that is not cracked at all is judged as “excellent”, and “◎” is added to the table. A sample that has a slight crack in the outermost layer but has not reached the substrate is judged as “good”. “○” is attached to the surface, and a slight crack has occurred in the outermost layer, but a substrate that is not cracked is judged as “good” and a “△” is attached to the table, The occurrences were judged as “impossible” and “x” was added to the table, and “over” or higher was regarded as a practical level.

As is clear from these results, in the conventional examples 1, 2, and 4 in which the surface reduction by rolling and the heat treatment are not performed, compared with the present invention example in which the surface reduction was performed, I understand that. The reflectance in the ultraviolet to near-ultraviolet region of 340 nm to 400 nm, particularly 375 nm, was better in the examples of the present invention, satisfying 60% or higher at 340 nm, 75% or higher at 375 nm, and 80% or higher at 400 nm. Further, in Conventional Example 3 in which the heat treatment was performed at 320 ° C. for 30 seconds after plating, the reflectance was lower than that of the present invention example, particularly in the visible light region. This is because the example of Patent Document 2 is an alumina substrate made of ceramics, whereas a lead frame material using a metal for the substrate as in the present invention is subjected to a heat treatment at 320 ° C. for 30 seconds. It is thought that diffusion of the base material and the substrate component occurs, and further, the heat treatment is performed in the atmosphere, so that the oxidation of the substrate component proceeds and the heat resistance is lowered as shown in Table 2. It is.
Moreover, when Ag thickness is thin, it turns out that it exists in the tendency which is inferior to heat resistance, as it exists in the prior art examples 2 and 4.

Further, in Reference Example 1, since the outermost layer has a coating thickness of 0.1 μm, it is inferior in heat resistance and improved in reflectance at wavelengths of 375 nm and 400 nm, but inferior to Invention Example 11, It can be seen that the surface coating thickness is preferably 0.2 μm or more.
Further, in Reference Example 2, since the processing rate at the time of rolling after forming the reflective layer is as low as 0.5%, the reflectance is improved as compared with that without rolling, but the level is not sufficient.
Further, in Reference Example 3, although the area reduction rate is over 80%, it is confirmed that the reflectivity and heat resistance are excellent, but the bending workability is inferior. For this reason, it is understood that the area reduction rate is preferably 1 to 80%. Furthermore, if the bending workability is also important, a surface reduction rate of 20 to 60% is more preferable.
Further, Reference Example 4 and Reference Example 5 are examples in which heat treatment (low temperature annealing) was performed after plating and rolling, but the reflectivity was reduced by about 10% overall, and the thermal history due to low temperature annealing was excessive. As a result, the reflectance decreased. Thus, it can be seen that when heat treatment is performed after rolling, it is necessary to apply it while fully considering the reflectance.

In FIG. 8, the result of having measured the reflectance in the prior art example 1 and the invention example 19 is shown. These are the results obtained by comparing the conventional example 1 which has been plated by a conventional method (no rolling process and no heat treatment) and the inventive example 19 which has been subjected to the rolling process after plating. Thus, it can be seen that the present invention example has extinction of the absorption peak at a wavelength of 345 to 355 nm, and exhibits a very excellent reflectance in the visible light region. This reflectivity is very close to the physical limit reflectivity of silver and shows an unprecedented reflectivity, and is used very favorably as a lead frame for an optical semiconductor device at a wavelength of 340 to 800 nm in the near ultraviolet to visible light range. I understand that I can do it. In addition, the result of the conventional example 1 shown in the figure seems to have a lower reflectance on the lower wavelength side than the case of the conventional example 3.

(Example 2)
As Example 2, a substrate having a width of 100 mm shown in Table 3 was pretreated in the same manner as in Example 1, and then electroplating treatment shown in Table 3 was performed in the same manner as in Example 1. Using a substrate having a plate thickness of 0.25 mm and 0.83 mm, Ag plating is performed on both sides of the substrate so that the Ag coating thickness after the rolling process is 3 μm, and then processing during the rolling process after forming the reflective layer Rolling was performed at a rate of 40% to obtain strips having sheet thicknesses of 0.15 mm and 0.5 mm. After punching with a press, electroplating is performed to form a plating film with good solder wettability only on the external lead portion using a resist mask, the resist is removed, and invention examples having the configurations shown in Table 3 39 to 50 and Reference Examples 6 to 9 were obtained.
For Conventional Examples 5 to 8, strips having a thickness of 0.15 mm and 0.5 mm and a width of 100 mm were subjected to press punching and then subjected to Ag plating to produce lead frames shown in Table 3.
In both cases, the width of the lead portion to be soldered was 3 mm and 0.5 mm.

(Evaluation method)
The lead frames of the invention examples, reference examples, and conventional examples obtained as described above were evaluated according to the following tests and standards. The results are shown in Table 4.
(2A) Reflectance measurement: In a spectrophotometer U-4100 (trade name, manufactured by Hitachi High-Technologies Corporation), continuous measurement was performed with a total reflectance ranging from 300 nm to 800 nm. Among these, Table 4 shows total reflectance (%) at a wavelength of 340 nm, a wavelength of 375 nm, a wavelength of 400 nm, a wavelength of 450 nm, and a wavelength of 600 nm.
In consideration of practicality, the total reflectance is 60% or more at a wavelength of 340 nm, 75% or more at a wavelength of 375 nm, 80% or more at a wavelength of 400 nm, and a visible light region. The required characteristics were 90% or more at wavelengths of 450 nm and 600 nm.
(2B) Solderability: The solder wetting time of the lead part was evaluated after heating in air at 150 ° C. for 3 hours in a solder checker (SAT-5100 (trade name, manufactured by Resuka Co., Ltd.)). The details of the measurement conditions were as follows, and it was determined that the solder wetting time was 1 second or less.
Solder type: Sn-3Ag-0.5Cu
Temperature: 250 ° C
Flux: Isopropyl alcohol-25% rosin Immersion speed: 25 mm / sec Immersion time: 10 seconds Immersion depth: 10 mm

According to Example 2, the following was found in the present invention example, the reference example, and the conventional example.
(A) If the plated Ag coating has a rolled reflective layer of 3 μm, the reflectance is as good as in Example 1.
(B) It was found that none of the inventive examples in which Ag, Sn, or Au was plated on the external lead as a plating film having good solder wettability had a problem of solderability.
(C) In the reference example in which the external lead is not plated with good solder wetting, there is no problem with a thin plate thickness and a wide width, but with a narrow width, the wetting time is slightly long. A thick plate and a wide width have a slightly longer wetting time, and a narrow width has a considerably longer wetting time.
(D) From (b) and (c) above, in applications that require a high level of soldering reliability, and in the case of a shape that is difficult to wet with solder due to the plate thickness and width, good solder wetting to external leads Plating is preferred.
In the above embodiment, an example in which pure metal (Ag, Sn, or Au) is plated as the plating on the external lead has been shown. However, it has been confirmed that these have the same effect even in an alloy.

1 Base 2 Reflecting layer (rolled layer)
3 Optical semiconductor element 4 Intermediate layer 5 Mold resin 6 Sealing resin 7 Bonding wire 8 Soldering improvement layer (Ag, Au, Sn, alloys thereof, etc.)

Claims (14)

A lead frame for an optical semiconductor device comprising a reflective layer on at least one surface or both surfaces of the outermost surface of the substrate, and a part or the entire surface of the substrate, wherein the reflective layer reflects at least light of the optical semiconductor element. in the outermost surface of the have a rolling by the tissue overall plastic deformation silver or silver alloy plating tissues, the processing rate by the rolling of the of the plating tissue than 60% or more 37%, the plasticity of the reflective layer The thickness after deformation is 0.2 to 10 μm, the reflectance of light with a wavelength of 340 nm is 60% or more, the reflectance of light with a wavelength of 375 nm is 75% or more, the reflectance of light with a wavelength of 400 nm is 80% or more, The reflectance of light having a wavelength of 450 nm and 600 nm is 90% or more, respectively, and the reflectance of light having a wavelength of 375 nm is larger than that of light having a wavelength of 340 nm. That, lead frame for an optical semiconductor device.   2. The lead frame for an optical semiconductor device according to claim 1, wherein the reflection layer is provided on the base via at least one metal layer to be heat resistant. 3. The silver or silver alloy forming the reflective layer is silver, silver-tin alloy, silver-indium alloy, silver-rhodium alloy, silver-ruthenium alloy, silver-gold alloy, silver-palladium alloy, silver-nickel alloy, silver - selenium alloy, a silver - antimony alloy or silver, - characterized in that it is a platinum alloy, a lead frame for an optical semiconductor device according to claim 1 or 2. Wherein the substrate, copper, copper alloy, iron, characterized by comprising the iron alloy, aluminum or an aluminum alloy, a lead frame for an optical semiconductor device according to any one of claims 1-3. The portion requiring at least soldering, silver, silver alloy, tin, tin alloy, characterized by comprising a plating layer made of either a gold or gold alloy, or any of claims 1-4 1 Item 2. A lead frame for an optical semiconductor device according to the item. A method of manufacturing a material of a lead frame for a semiconductor device according to any one of claims 1-4, silver reflective area for reflecting light at least the optical semiconductor device emits a top surface of the substrate or A reflective layer made of a silver alloy is formed by electroplating, electroless plating, or sputtering, and then subjected to rolling to plastically deform the plated structure. % Or more and 60% or less, A method for producing a lead frame material for an optical semiconductor device. A method of manufacturing a semiconductor device lead frame as claimed in any one of claims 1-4, base silver or a silver alloy in the reflective region to reflect light at least the optical semiconductor device emits a top surface of the After forming the reflective layer comprising an electroplating method, electroless plating method or sputtering method, a rolling process is performed to obtain a lead frame material for an optical semiconductor device in which the plating structure is plastically deformed. Alternatively, the lead frame for an optical semiconductor device is manufactured by performing a punching process by an etching method to obtain a lead frame, and the processing rate of the rolling process of the plated structure is 37% or more and 60% or less. Method. 8. The method of manufacturing a lead frame for an optical semiconductor device according to claim 7 , wherein plating with good solderability is partially applied after the punching process. The plating with good solderability is applied to at least a region other than the region that reflects light emitted from the optical semiconductor element, and the plating component is silver, silver alloy, tin, tin alloy, gold, or gold alloy. The method for manufacturing a lead frame for an optical semiconductor device according to claim 8 , wherein the method is any one of the above. An optical semiconductor device comprising an optical semiconductor element and the lead frame for an optical semiconductor device according to any one of claims 1 to 5 , wherein the reflective layer of the lead frame for an optical semiconductor device is a base. An optical semiconductor device characterized in that the optical semiconductor device is provided in a region that reflects at least light generated from the optical semiconductor element and has a plastically deformed plating structure. The optical semiconductor device according to claim 10 , wherein an emission wavelength of the optical semiconductor element is 340 nm to 800 nm. And wherein the light output from the device is a white light, an optical semiconductor device according to claim 10 or 11. And wherein the light output from the device is ultraviolet, a near-ultraviolet or ultraviolet light, an optical semiconductor device according to claim 10 or 11. An illuminating device comprising the optical semiconductor device according to any one of claims 10 to 13 .

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