JP2010206034A - Lead frame for optical semiconductor device, package for the optical semiconductor device, the optical semiconductor device, production method of lead frame for optical semiconductor device, production method of package for the optical semiconductor device, and production method of the optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably secure superior light emission rate, while making the light emission characteristics stabilize. <P>SOLUTION: By forming a silver coating film 007 on one or more layers of coating films (003, 004, 005) formed on a substrate 002 for a lead frame via a coating film 006 acting as a sacrificial anode, discoloration of the silver coating film 007 by heating and a diffusion of a metal element are suppressed; and thereby superior light emission rate can be secured stably, while light emission characteristics are stabilized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical semiconductor device lead frame having a silver film formed on a surface layer, an optical semiconductor device package using the lead frame, an optical semiconductor device using the optical semiconductor device package, and methods of manufacturing the same.

  In recent years, optical semiconductor devices such as light emitting diodes (LEDs) and laser diodes (LDs) are required to have high luminous efficiency. Further, there is a strong demand for a package for an optical semiconductor device that maintains high reliability for a long time in both miniaturization and high output.

  Recently, there are optical semiconductor device packages in which a silver film excellent in reflectivity at a visible light wavelength of around 400 nm is formed on the outermost layer and an optical semiconductor device using the same, and the manufacturing process is heated. There are an optical semiconductor device package and an optical semiconductor device using the same, which have a structure for improving heat dissipation in order to reduce the influence of heating such as brown discoloration due to the above.

  7 is a cross-sectional view showing a conventional optical semiconductor device package and the structure of the optical semiconductor device. FIG. 7A is a cross-sectional view of the optical semiconductor device package, and FIG. 7B is a cross-sectional view of FIG. FIG. 7C is an enlarged view of a portion B in FIG. 7A. FIG. 7C is an optical semiconductor device using the package for the optical semiconductor device.

  In FIG. 7, a package 103 for an optical semiconductor device has a cavity 103 formed as an insulating material by opening the surface side of a substrate 102 made of, for example, alumina ceramic. A conductive pad 103 b made of a metal layer is formed on the bottom surface 103 a of the cavity 103, and a semiconductor element 104 is mounted and connected by a conductive wire 105. The substrate 102 has the external terminal 103 c exposed and is connected to the conductive pad 103 b in the cavity 103 to constitute the semiconductor device 107.

By making the silver plating layer 106 applied under the conductive pad 103b 5 μm or more, heat dissipation is improved, and the influence of heating is alleviated to prevent or suppress brown discoloration (see, for example, Patent Document 1).
JP 2008-16593 A

  However, in the configuration in which the silver plating layer 106 is formed directly on the substrate 102, the influence of heating can be reduced by increasing the thickness of the silver plating layer 106, but in proportion to the increase in the amount of heat applied to the silver plating layer 106. It is necessary to form the silver plating layer 106 thick. As a result, the accuracy of the thickness dimension at the time of film formation becomes unstable, the positional accuracy at which the semiconductor element 104 is mounted is lowered, and the light emission characteristics are not stable. Furthermore, this leads to an increase in the amount of material used, increasing the cost burden.

  In addition, due to the thermal history and changes with time, metal diffusion from the conductive pad 103b formed thereon into the silver plating layer 106 is promoted, and a diffusing substance appears on the surface of the silver plating layer 106. Since the surface of the plating layer 106 is discolored and the reflectance cannot be stably maintained, the reflectance is lowered.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to stably ensure a good light emission rate while stabilizing the light emission characteristics.

  In order to solve the problems of the prior art, an optical semiconductor device lead frame of the present invention is an optical semiconductor device lead frame including a mounting region on which an optical semiconductor element is mounted, the lead frame base material, As a sacrificial anode, one or a plurality of layers of films formed on a lead frame base material, a film acting as a sacrificial anode made of a metal film lower than silver formed in the mounting region on the film, and It has the silver film formed on the film | membrane which acts.

  In addition, the coating is a multilayer film of nickel or an alloy coating thereof as the first layer of the lowermost layer, palladium or an alloy coating thereof as the second layer, and gold or an alloy coating thereof as the third layer of the uppermost layer. To do.

  The film acting as a sacrificial anode is copper or an alloy film thereof, nickel or an alloy film thereof, tin or an alloy film thereof, zinc or an alloy film thereof, or a mixed layer thereof.

The optical semiconductor device package according to the present invention is characterized in that a resin envelope is formed on the silver film around the mounting region with respect to the lead frame for an optical semiconductor device.
The optical semiconductor device according to the present invention is characterized in that an optical semiconductor element is mounted in the mounting region with respect to the optical semiconductor device package, and the optical semiconductor element is sealed with a translucent resin.

  Furthermore, in the method for manufacturing a lead frame for an optical semiconductor device according to the present invention, when manufacturing a lead frame for an optical semiconductor device having a mounting area for mounting an optical semiconductor element, one or more layers of coatings are formed on the substrate for the lead frame. Forming a film that acts as a sacrificial anode made of a metal film lower than silver on the mounting region on the film, and selectively forming a silver film on the film acting as the sacrificial anode And a step of forming.

  The method for manufacturing an optical semiconductor device package according to the present invention includes a step of forming a coating of one or more layers on a lead frame base material, and a metal coating lower than silver in the mounting region on the coating. Forming a film acting as a sacrificial anode, selectively forming a silver film on the film acting as the sacrificial anode, and forming a resin envelope on the silver film around the mounting region And a step of performing.

  The method for manufacturing an optical semiconductor device according to the present invention includes a step of forming one or a plurality of layers on a lead frame substrate, and a sacrifice made of a metal coating that is baser than silver on the mounting region on the coating. Forming a film acting as an anode, selectively forming a silver film on the film acting as a sacrificial anode, and forming a resin envelope on the silver film around the mounting region And a step of mounting the optical semiconductor element in the mounting region, and a step of sealing the optical semiconductor element with a translucent resin.

  As described above, it is possible to stably ensure a good light emission rate while stabilizing the light emission characteristics.

  As described above, a silver coating is formed on one or a plurality of coatings formed on a substrate via a coating that acts as a sacrificial anode, whereby the silver coating is discolored by heating, and the metal element is It is possible to suppress the diffusion and to stably and satisfactorily secure a light emission rate while stabilizing the light emission characteristics.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a sectional view showing the structure of a lead frame for an optical semiconductor device according to the present invention.

  As shown in FIG. 1, an optical semiconductor device lead frame 001 is obtained by forming a metal film after forming a lead frame substrate 002 such as an iron alloy or a copper alloy by a molding technique such as pressing or etching. . The metal film is composed of, for example, nickel or its alloy film 003 as the first layer, palladium or its alloy film 004 as the second layer, and gold or its alloy film 005 as the third layer. Furthermore, copper or its alloy film as a fourth layer on the gold or its alloy film 005 and on a part of the lead portion which becomes a region in the resin envelope added in the package for an optical semiconductor device described later, A film 006 acting as a sacrificial anode, such as nickel or an alloy film thereof, tin or an alloy film thereof, or zinc or an alloy film thereof, or a mixed film thereof, and a silver film 007 as the fifth layer are laminated in this order. . In the lead frame 001 for an optical semiconductor device having such a configuration, in the lead portion in the resin envelope, discoloration of the surface of the silver coating 007 is suppressed by the coating 006 acting as a sacrificial anode, and an excellent light reflectance is obtained. In addition, since the generation of metal oxides on the silver surface is suppressed, the wire bonding property is prevented from being deteriorated, and a sealing resin that easily allows moisture and air to pass through is used as the sealing resin in the optical semiconductor device. However, since the base copper or its alloy film, nickel or its alloy film, tin or its alloy film, zinc or its alloy film is preferentially corroded as a sacrificial anode, the outermost silver film 007 corrodes. It has difficult characteristics, and since the gold or its alloy film 005 is exposed in parts other than the resin envelope, corrosion resistance and lead-free soldering That has excellent properties in high-temperature solderability. Furthermore, since the influence of heating is reduced, it is not necessary to make the silver film 007 thicker than 5 μm.

  Each film thickness is, for example, 0.5 to 2.0 μm for nickel, 0.005 to 0.07 μm for palladium, 0.003 to 0.01 μm for gold, 0.01 μm or more for copper, and 2.0 μm for silver. It is. Here, the silver film needs to have a film thickness of at least 1.5 μm in order to prevent copper diffusion due to thermal history in the D / B or W / B process.

  Here, the sacrificial anode will be described. Usually, when two different metals come into contact with each other in an environment where moisture and oxygen are present, battery action corrosion occurs in which corrosion proceeds from a base metal (a metal having a high ionization tendency). In the metal film configuration, when the film 006 acting as a sacrificial anode is not present, the gold or alloy film 005 and the silver film 007 are in direct contact with each other, and corrosion proceeds from the silver film 007, which is a base metal. Therefore, the presence of a base metal film as a sacrificial anode between the layers of gold or its alloy film 005 and silver film 007 is preferentially corroded from the metal, and the corrosion of the outermost silver film 007 is suppressed. Can be made. At this time, the film 006 acting as a sacrificial anode needs to be formed so that the gold or alloy film 005 and the silver film 007 do not contact at all.

  2 is a cross-sectional view showing the structure of the optical semiconductor device package of the present invention. FIG. 2 (a) is a cross-sectional view of the optical semiconductor device package, and FIGS. 2 (b) and 2 (c) are FIG. It is the A section enlarged view of a).

  The optical semiconductor device lead frame 001 is the same as that shown in FIG. The resin envelope 008 is formed around the area where the optical semiconductor element of the optical semiconductor device lead frame 001 is mounted. Here, as shown in FIG. 2 (b), the coating 006 acting as a sacrificial anode may be provided only directly below the silver coating 007. However, as shown in FIG. 2 (c), the resin envelope When a coating 006 that acts as a sacrificial anode is present in a part or all of the portion where 008 and the optical semiconductor device lead frame 001 are in contact with each other, the coating that acts as a sacrificial anode Since a metal oxide is generated on the outermost surface of 006 to improve the bonding force with the functional group having polarity contained in the sealing resin, the lead frame 001 for the optical semiconductor device and the resin envelope 008 It is even better because the adhesiveness is improved by the sealing resin flowing into the minute gap.

FIG. 3 is a sectional view showing the structure of the optical semiconductor device of the present invention.
In addition, the same code | symbol is attached | subjected to the part which is the same as that of the said FIGS. 1-2, or corresponds, and the description is abbreviate | omitted.

  In FIG. 3, an optical semiconductor element 009 is mounted in a region where the optical semiconductor element of the package for an optical semiconductor device is mounted. After wire bonding, the optical semiconductor element 009 is sealed with a sealing resin 010 to form an optical semiconductor device. The sealing resin used at this time includes an epoxy resin, a silicone resin, etc., but even when using a sealing resin that allows water and air to pass through like a silicone resin, copper or its alloy film as the base is used. Since nickel or an alloy film thereof, tin or an alloy film thereof, or zinc or an alloy film thereof is preferentially corroded as a sacrificial anode, the outermost silver film 007 has a property of being hardly corroded.

  As described above, in the optical semiconductor device lead frame, the optical semiconductor device package using the optical semiconductor device, and the optical semiconductor device according to the present invention, at least the optical semiconductor element on one or more layers of the coating formed on the substrate is mounted. The silver coating is discolored by heating and the metallic element is diffused by forming a silver coating on the region where the resin envelope around the region to be formed is formed through a coating that acts as a sacrificial anode. Since it is no longer necessary to increase the film thickness of the silver coating, it is possible to maintain the gloss of the surface of the silver coating and ensure a good luminous rate stably while ensuring the accuracy of mounting the semiconductor element and stabilizing the light emission characteristics. can do.

(Embodiment 2)
FIG. 4 is a process cross-sectional view illustrating a method for manufacturing a lead frame for an optical semiconductor device according to the present invention, and FIGS. 4E and 4F are enlarged views of a B portion.

  A lead frame substrate 002 such as an iron alloy or a copper alloy as shown in FIG. 4A is formed on an optical semiconductor device lead frame 001 as shown in FIG. 4B by pressing or etching. Next, as shown in FIG. 4C, a metal film is formed on the lead frame 001 for optical semiconductor devices by plating or the like. The structure of this film is, for example, nickel or its alloy film 003 for the first layer, palladium or its alloy film 004 for the second layer, and gold or its alloy film 005 for the third layer. Thereafter, as shown in FIG. 4 (d), copper or its alloy film, nickel or the like on the metal film, for example, on the gold or its alloy film 005 and on the lead where the resin envelope 008 is formed. A coating 006 and a silver coating 007 that act as sacrificial anodes such as the alloy coating, tin or the alloy coating, or zinc or the alloy coating are formed in this order. At this time, the film 006 acting as a sacrificial anode is formed so that the gold or alloy film 005 and the silver film 007 do not contact at all.

  As a method for producing such a film, a method in which both the copper or its alloy film 006 and the silver film 007 are partially plated by masking with a mechanical mask or a resist film, the copper or its alloy film 006 is entirely plated, The silver film 007 is a method in which partial plating is performed by masking with a mechanical mask or a resist film, and then the excess copper is removed with a copper remover or a chemical polishing solution. The copper or alloy film 006 is entirely plated, and the silver film 007 is a method in which partial plating is performed by masking with a mechanical mask or a resist film, and after forming the resin envelope 008, there is a method of removing excess copper with a copper remover or chemical polishing liquid. In the method of removing excess copper after plating, the cross section of copper plating becomes uneven, so anchors As a result, the adhesion with the sealing resin is improved (FIG. 4E), and in the method in which the copper plating is peeled off after molding, the interlayer between the resin envelope 008 and the lead frame 001 becomes copper plating, and the copper plating is performed. The oxide film 011 formed on the outermost surface is even better for improving the adhesion between the lead frame 001 and the sealing resin flowing into the minute gap between the resin envelope 008 (FIG. 4F). The lead frame for an optical semiconductor device manufactured by such a manufacturing method has a characteristic that the outermost silver film 007 is hardly corroded.

FIG. 5 is a process cross-sectional view illustrating a method for manufacturing an optical semiconductor device package according to the present invention. FIGS. 5 (e) and 5 (f) are enlarged views of a portion C.
An optical semiconductor device lead frame 001 as shown in FIG. 5A is placed in close contact with the resin envelope molding die 012 as shown in FIG. 5B. A space (cavity) is formed in the resin envelope molding die 012, and a thermoplastic resin such as PPA (polyphthalamide) is injected into the space to obtain a light as shown in FIG. A resin envelope 008 in which the semiconductor device lead frame 001 is sealed is formed to form an optical semiconductor device package. At the time of insert molding of the resin envelope 008, a minute gap 013 between the optical semiconductor device lead frame 001 and the resin envelope 008 is formed by heat shrinkage, and the sealing is performed during the subsequent resin sealing. The resin flows into the minute gap 013 and comes into contact with the exposed copper, whereby the adhesion is improved (FIGS. 5E and 5F).

FIG. 6 is a process cross-sectional view illustrating the method for manufacturing the optical semiconductor device of the present invention.
In a package for an optical semiconductor device as shown in FIG. 6A, a semiconductor element 014 is placed on a lead frame 001 for an optical semiconductor device as shown in FIG. The electrical connection region of the frame 001 is wire-bonded with a conductive wire such as a gold wire or an aluminum wire. Next, as shown in FIG. 6C, the optical semiconductor device is completed by sealing with a light-transmitting sealing resin 015 such as a transparent silicone resin. At this time, the sealing resin 015 flowing into the minute gap 013 (see FIG. 5) between the lead frame 001 for the optical semiconductor device and the resin envelope 008 generated by the thermal shrinkage at the time of molding is the exposed copper. It adheres strongly. In the optical semiconductor device manufactured by such a method, in the lead portion in the resin envelope, excellent light reflectivity and wire bonding property can be obtained, and moisture and air such as silicone resin can be easily transmitted. Even when a stop resin is used, since the base copper or its alloy film, nickel or its alloy film, tin or its alloy film, zinc or its alloy film, etc. are preferentially corroded as a sacrificial anode, The film 007 (see FIG. 5) has a characteristic that it is difficult to corrode.

  Further, the portions other than the resin envelope have excellent characteristics such as corrosion resistance and high temperature solderability by lead-free solder.

  INDUSTRIAL APPLICABILITY The present invention can ensure a stable and good light emission rate while stabilizing the light emission characteristics, and manufacture of a lead frame for optical semiconductor devices, a package for optical semiconductor devices, an optical semiconductor device, and a lead frame for optical semiconductor devices. This method is useful for a method, a method for manufacturing an optical semiconductor device package, a method for manufacturing an optical semiconductor device, and the like.

Sectional drawing which shows the structure of the lead frame for optical semiconductor devices of this invention Sectional drawing which shows the structure of the package for optical semiconductor devices of this invention Sectional drawing which shows the structure of the optical semiconductor device of this invention Process sectional drawing which shows the manufacturing method of the lead frame for optical semiconductor devices of this invention Process sectional drawing which shows the manufacturing method of the package for optical semiconductor devices of this invention Process sectional drawing which shows the manufacturing method of the optical semiconductor device of this invention Sectional drawing which shows the structure for the conventional package for optical semiconductor devices, and an optical semiconductor device

001 Lead frame for optical semiconductor device 002 Lead frame substrate 003 Nickel or alloy film 004 Palladium or alloy film 005 Gold or alloy film 006 Film 007 acting as a sacrificial anode Silver film 008 Resin envelope 009 Optical semiconductor element 010 Sealing resin 011 Oxide film 012 Resin envelope molding die 013 Small gap 014 Half device element 015 Sealing resin 101 Package for optical semiconductor device 102 Base 103 Cavity 103a Bottom surface 103b Conductive pad 103c External terminal 104 Semiconductor element 105 Conductive wire 106 Silver plating layer 107 Semiconductor device

Claims (8)

An optical semiconductor device lead frame comprising a mounting area for mounting an optical semiconductor element,
A lead frame substrate;
One or more layers formed on the lead frame substrate; and
A film that acts as a sacrificial anode consisting of a metal film that is baser than silver formed in the mounting region on the film;
A lead frame for an optical semiconductor device, comprising: a silver film formed on the film acting as the sacrificial anode.   The film is a laminated film of nickel or an alloy film thereof as a first layer as a lowermost layer, palladium or an alloy film thereof as a second layer, and gold or an alloy film thereof as a third layer as an uppermost layer. Item 12. A lead frame for an optical semiconductor device according to Item 1.   The film acting as a sacrificial anode is copper or an alloy film thereof, nickel or an alloy film thereof, tin or an alloy film thereof, zinc or an alloy film thereof or a mixed layer thereof. Item 3. The lead frame for an optical semiconductor device according to any one of Items 2 to 3. With respect to the lead frame for an optical semiconductor device according to any one of claims 1 to 3,
A package for an optical semiconductor device, wherein a resin envelope is formed on the silver film around the mounting region. With respect to the optical semiconductor device package according to claim 4,
An optical semiconductor element is mounted on the mounting area,
An optical semiconductor device, wherein the optical semiconductor element is sealed with a translucent resin. When manufacturing a lead frame for an optical semiconductor device having a mounting area for mounting an optical semiconductor element,
Forming a film of one or more layers on the lead frame substrate;
Forming a film that acts as a sacrificial anode made of a metal film that is lower than silver in the mounting region on the film;
And a step of selectively forming a silver film on the film acting as the sacrificial anode. Forming a film of one or more layers on the lead frame substrate;
Forming a film that acts as a sacrificial anode made of a metal film that is lower than silver in the mounting region on the film;
Selectively forming a silver film on the film acting as the sacrificial anode;
Forming a resin envelope on the silver film around the mounting region. A method for manufacturing a package for an optical semiconductor device, comprising: Forming a film of one or more layers on the lead frame substrate;
Forming a film that acts as a sacrificial anode made of a metal film that is lower than silver in the mounting region on the film;
Selectively forming a silver film on the film acting as the sacrificial anode;
Forming a resin envelope on the silver film around the mounting region;
Mounting an optical semiconductor element in the mounting region;
And a step of sealing the optical semiconductor element with a translucent resin.

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