JP6829665B2 - Lead frame, semiconductor device, and lead frame manufacturing method - Google Patents

Description

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

There are various types of semiconductor devices equipped with semiconductor elements such as LSI (Large Scale Integration). Among them, semiconductor devices in which semiconductor elements are mounted on lead frames are widely used because lead frames can be manufactured at low cost by etching or press working.

In the semiconductor device, the semiconductor element and the lead frame are electrically connected by bonding wires. Therefore, if the adhesion between the bonding wire and the lead frame is poor, the bonding wire may be peeled off from the lead frame, and the reliability of the semiconductor device may be lowered.

Japanese Unexamined Patent Publication No. 2012-23102 Japanese Unexamined Patent Publication No. 60-223147

According to one aspect, it is an object of the present invention to provide a lead frame, a semiconductor device, and a method for manufacturing a lead frame capable of improving adhesion to a metal wire such as a bonding wire.

According to one aspect, it has a metal plate, a polymer film formed on the surface of the metal plate and containing a polymer of either titanium oxide or zirconium oxide, and a silver film formed on the polymer film. Lead frames are provided.

According to one aspect, the crystal grains of the silver film become finer by the action of the polymerized film, and the unevenness of the surface of the silver film can be made finer. As a result, in addition to the adhesive force derived from the metal bonding property between the metal wire and the silver film, the adhesive force between the metal wire and the silver film can be enhanced by the anchor effect due to the unevenness of the surface of the silver film.

FIG. 1 is a plan view of the copper plate used in the survey. FIG. 2 is a flowchart showing a method of forming a polymer film. 3 (a) and 3 (b) are cross-sectional views (No. 1) during the production of the sample. 4 (a) and 4 (b) are cross-sectional views (No. 2) during the production of the sample. FIG. 5 is a diagram showing an example of a titanium chelate solution, an oligomer solution, and a zirconium chelate solution. FIG. 6 is a diagram showing an example of each component in the solution and the concentration of the component in the solution. FIG. 7 is a cross-sectional view of a sample according to a comparative example. FIG. 8 is a diagram showing the results of investigation of the glossiness of the silver film. FIG. 9 is a diagram schematically showing the appearance of each sample. FIG. 10 is an image obtained by observing the surface of the silver film with an SEM (Scanning Electron Microscope). 11 (a) and 11 (b) are cross-sectional views (No. 1) of the semiconductor device according to the present embodiment during manufacturing. 12 (a) and 12 (b) are cross-sectional views (No. 2) of the semiconductor device according to the present embodiment during manufacturing. 13 (a) and 13 (b) are cross-sectional views (No. 3) of the semiconductor device according to the present embodiment during manufacturing. 14 (a) and 14 (b) are cross-sectional views (No. 4) of the semiconductor device according to the present embodiment during manufacturing. 15 (a) and 15 (b) are cross-sectional views (No. 5) of the semiconductor device according to the present embodiment during manufacturing. 16 (a) and 16 (b) are plan views (No. 1) of the semiconductor device according to the present embodiment during manufacturing. 17 (a) and 17 (b) are plan views (No. 2) of the semiconductor device according to the present embodiment during manufacturing. 18 (a) and 18 (b) are plan views (No. 3) of the semiconductor device according to the present embodiment during manufacturing. 19 (a) and 19 (b) are plan views (No. 4) of the semiconductor device according to the present embodiment during manufacturing. FIG. 20 is a plan view of the semiconductor device according to the present embodiment as viewed from the second main surface side of the metal plate.

Prior to the description of the present embodiment, the matters examined by the inventor of the present application will be described.

A metal wire such as a gold wire is connected to the surface of the lead frame by wire bonding, and a silver film may be formed on the surface of the lead frame in order to improve the adhesion with the metal wire.

Since the silver film is less likely to be oxidized than the metal such as copper used for the lead frame, it is possible to prevent the lead frame from being oxidized by the heat during wire bonding, and as a film formed on the uppermost layer of the lead frame. Suitable.

The silver film is formed by an electroplating method using a cyanide bath, and irregularities reflecting silver crystal grains are formed on the surface thereof. The adhesion of the metal wire to the silver film depends on the shape of the unevenness, and the adhesion between the metal wire and the silver film can be improved by forming an appropriate uneven shape.

Further, in a lead frame for a light emitting element such as an LED (Light Emitting Diode), the silver film also functions as a reflecting film that reflects the light emitted from the light emitting element to enhance the light intensity. In this case, if the surface of the silver film has large irregularities, the gloss of the silver film is lost, and the light of the light emitting element cannot be reflected well by the silver film.

Therefore, in order to improve the adhesion to the metal wire and efficiently reflect the light of the light emitting element, the crystal grains contained in the silver film are made as small as possible to make the surface irregularities of the silver film fine. It is preferable to make it.

The size of the crystal grains can be made finer to some extent by adding a brightener to the silver plating solution.

Table 1 below is an example of compounds used as brighteners.

These compounds strongly adsorb to the surface of the lead frame during electroplating and act to suppress the reduction reaction of silver on the surface. As a result, the growth of silver crystal nuclei on the surface of the lead frame is inhibited by these compounds, and silver crystal grains can be refined.

However, the concentration of the brightener in the silver plating solution is extremely small, from several mg / liter to several g / liter, and even a slight change in the concentration greatly changes the appearance of silver plating. Has the problem that it is difficult to control the concentration of the brightener.

The inventor of the present application conducted the following investigation in order to refine the crystal grains in the silver film without using a brightener.

FIG. 1 is a plan view of the copper plate used in the survey.

The copper plate 1 is a metal plate simulating a lead frame and has a rectangular planar shape.

Then, a titanium oxide polymer film was formed on the surface of the copper plate 1 as follows.

FIG. 2 is a flowchart showing a method of forming the polymerized film. Further, FIGS. 3 to 4 are cross-sectional views during the production of the sample using the copper plate 1.

First, in step S1 of FIG. 2, the copper plate 1 is cleaned by immersing the copper plate 1 in an alkaline degreasing agent having a liquid temperature of about 40 ° C. to 60 ° C. and maintaining the state for about 5 minutes.

After that, the copper plate 1 is pulled up from the degreasing agent.

Next, the process proceeds to step S2, and the copper plate 1 is washed with water for a time of about 20 to 60 seconds.

Next, the process proceeds to step S3, and the surface of the copper plate 1 is dried with air.

Subsequently, the process proceeds to step S4, in which the copper plate 1 is immersed in IPA (Isopropyl Alcohol) to replace the water remaining on the surface of the copper plate 1 with IPA.

Then, the process proceeds to step S5, and the surface of the copper plate 1 is dried with air.

After that, the process proceeds to step S6, and the copper plate 1 is immersed in the organometallic complex solution.

FIG. 3A is a diagram schematically showing step S6.

In the example of FIG. 3A, the titanium chelate solution 3 is placed in the container 2, and the copper plate 1 is immersed in the solution 3. The temperature of the solution 3 is room temperature, and the immersion time is about 20 to 60 seconds.

The solution 3 is prepared by diluting an organometallic complex solution such as a commercially available titanium chelate solution with a diluting solvent.

FIG. 5 is a diagram showing an example of a commercially available organometallic complex solution manufactured by Matsumoto Fine Chemicals Co., Ltd.

In this example, any of the organometallic complex solutions of FIG. 5 is used. As shown in FIG. 5, the organometallic complex solution is not limited to the titanium chelate solution, and a titanium oligomer solution or a zirconium chelate solution may be used as the organometallic complex solution.

These organometallic complex solutions are divided into a solvent system containing an organic solvent and an aqueous solvent system. Of these, when a solvent-based organometallic complex solution is used, the organometallic complex solution can be uniformly adhered to the surface of the copper plate 1 by replacing the water content of the copper plate 1 with IPA in step S4.

FIG. 6 is a diagram showing an example of each component in the solution 3 and the concentration of the component in the solution 3.

As shown in FIG. 6, solution 3 is made from an organometallic complex solution, a diluting solvent, a surfactant, and a thickener.

The concentration of the organometallic complex solution in Solution 3 is 0.1 vol% to 10 vol%, and the concentration of the surfactant is 0.01 vol% to 1 vol%. The concentration of the thickener in Solution 3 is 0.1 wt% to 10 wt%.

Although a plurality of materials are listed as an example of the diluting solvent in FIG. 6, at least one of these materials may be used as the diluting solvent. The same applies to surfactants and thickeners.

See FIG. 2 again.

After immersing the copper plate 1 in the solution 3 as described above, the process proceeds to step S7, and the copper plate 1 is pulled up from the solution 3.

FIG. 3B is a cross-sectional view of the copper plate 1 when pulled up from the solution 3 in this way.

As shown in FIG. 3B, a coating film 4 of the solution 3 is formed on the surface of the copper plate 1.

The method of forming the coating film 4 by immersing the copper plate 1 in the solution 3 in this way is called dip coating. The method for forming the coating film 4 is not limited to dip coating, and the coating film 4 may be formed by spin coating or a sol-gel method.

In this example, since the thickener is added to the solution 3 as described above, the thickness of the coating film 4 can be made uniform by the solution 3 having an appropriate viscosity.

The thickness of the coating film 4 can be controlled by the immersion time of the copper plate 1 in the solution 3, and the longer the immersion time, the thicker the coating film 4 can be obtained.

The thickness of the coating film 4 is not particularly limited, but in this example, the thickness of the coating film 4 is about 5 nm to 50 nm. The reason why the lower limit of the thickness is set to 5 nm is that if it is thinner than this, it becomes difficult to control the size of the crystal grains of the silver film to be formed later on the coating film 4. Further, the upper limit of the thickness is set to 50 nm because the adhesion between the silver film and the coating film 4 decreases when the thickness is made thicker than this.

See FIG. 2 again.

Next, the process proceeds to step S8, in which the coating film 4 is heated to a temperature of about 100 ° C. to 300 ° C. in an oven (not shown), and the state is maintained for about 30 seconds.

As a result, as shown in the following formula (1), the titanium chelate (Ti (OR) ₄ : R is an alkyl group) contained in the coating film 4 is hydrolyzed and the hydrolysis product (Ti (OR) ₃ OH) is hydrolyzed. ) Is generated, and the solvent of the coating film 4 is removed by heating.

Hereinafter, such heat treatment is also referred to as prebaking.

In order to prevent the surface of the copper plate 1 from being oxidized during the prebaking, it is preferable to carry out this step in an inert atmosphere such as nitrogen gas.

Next, the process proceeds to step S9 of FIG. 2, in which the coating film 4 is heated to a temperature of about 100 ° C. to 300 ° C. in an oven (not shown), and the state is maintained for a time of about 1 minute to 60 minutes.

FIG. 4A is a cross-sectional view of the copper plate 1 when heated in this way.

By this heating, as shown in the following formula (2), the titanium chelate (Ti (OR) ₄ ) remaining in the coating film 4 and the hydrolysis product (Ti (OR) ₃ OH) undergo a polycondensation reaction. A dialkoxy titanium polymer is produced.

Then, the dialkoxytitanium polymer reacts with the moisture in the air to form a titanium oxide polymer, and the coating film 4 becomes a polymer film 5 containing the polymer.

The titanium oxide polymer contained in the polymer film 5 has a three-dimensional network structure as shown in the following formula (3).

When a zirconium chelate is used instead of the titanium chelate contained in the solution 3 (see FIG. 3A), the polymer film 5 contains a zirconium oxide polymer.

After forming the polymerized film 5 as described above, as shown in FIG. 4B, a silver film 6 is formed on the polymerized film 5 by an electroplating method.

The composition of the silver plating solution for forming the silver film 6 is not particularly limited. However, since it is difficult to adjust the concentration of the brightener as described above, none of the brighteners shown in Table 1 is added to the silver plating solution.

In this example, a solution containing each of the following components is used as the silver plating solution containing no brightener.

・ Silver potassium cyanide (KAg (CN) ₂ )… Concentration 120 g / liter ・ Potassium cyanide (KCN)… Concentration 5 g / liter ・ Dipotassium hydrogen phosphate (K ₂ HPO ₄ )… Concentration 20 g / liter ・ Boric acid (H ₃₎ BO ₃ )… With a concentration of 10 g / liter or more, the sample P1 used in this study was completed.

In order to evaluate the function of the polymerized film 5, the inventor of the present application also prepared a sample according to a comparative example in which the polymerized film 5 is not formed.

FIG. 7 is a cross-sectional view of sample P2 according to the comparative example.

In sample P2, the silver film 6 was directly formed on the copper plate 1 by the electroplating method. Similar to sample P1, in sample P2, no brightener was added to the silver plating solution of the silver film 6.

Then, a heating test of heating each of the samples P1 and P2 to a temperature of 200 ° C., which corresponds to the heating temperature at the time of wire bonding, was carried out for 60 minutes, and the glossiness of the silver film 6 after the heating test was investigated.

The survey results are shown in FIG.

In the investigation, the elements contained on the surface of the silver film 6 were investigated by GDS (Glow Discharge optical emission Spectrometry), and whether or not the silver film 6 contained copper was also investigated.

As shown in FIG. 8, in sample P1, the glossiness of the silver film 6 was as high as 0.85, and copper was not detected in the silver film 6.

A plating film having a glossiness of more than 0.8 is called a glossy plating film, and it was revealed that the silver film 6 becomes a glossy plating film in sample P1.

Further, since copper was not detected in the silver film 6, it was clarified that the polymer film 5 has a function as a diffusion prevention film for preventing the copper of the copper plate 1 from diffusing into the silver film 6.

On the other hand, in sample P2 according to the comparative example, the glossiness of the silver film was as low as 0.33, and copper was detected in the silver film 6.

FIG. 9 is a diagram schematically showing the appearance of each of the samples P1 and P2.

As shown in FIG. 9, the surface of the silver film 6 is glossy in the sample P1, whereas the surface of the silver film 6 is dull in the sample P2 according to the comparative example.

Further, the inventor of the present application observed the surface of the silver film 6 immediately after plating and the surface of the silver film 6 after the above heating test with an SEM (Scanning Electron Microscope).

The observation result is shown in FIG.

As shown in FIG. 10, in the silver film 6 of the sample P1, the crystal grains are extremely fine both immediately after plating and after the heating test.

On the other hand, in the silver film 6 of the sample P2 according to the comparative example, the crystal grains are larger than those of the sample P1 both immediately after plating and after the heating test.

From the above results, by forming a titanium oxide polymer film 5 on the surface of the copper plate 1 and forming a silver film 6 on the polymer film 5 by an electroplating method, a brightener is added to the silver plating solution of the silver film 6. It was clarified that the silver film 6 having fine surface irregularities and gloss was obtained without adding the above.

When the unevenness of the surface is made finer in this way, the adhesion between the silver film 6 and the metal wire can be enhanced.

Further, when the copper of the copper plate 1 diffuses into the silver film 6, the adhesion between the metal wire and the silver film 6 may be hindered by the copper, but as described above, the polymerized film 5 functions as a copper diffusion prevention film. Therefore, it is possible to suppress a decrease in the adhesive force between the metal wire and the silver film 6 due to the copper diffused in the silver film 6.

In the above investigation, the polymer film 5 was formed on the surface of the copper plate 1, but according to another investigation conducted by the inventor of the present application, even if the polymer film 5 is formed on the gold film, the polymer film 5 is formed. It was confirmed that a glossy silver film 6 could be formed on the film.

The present embodiment will be described below.

(This Embodiment)
In the present embodiment, a lead frame is manufactured as follows, and a semiconductor device in which a light emitting element is mounted on the lead frame is manufactured.

The semiconductor element mounted on the lead frame is not limited to the light emitting element, and the LSI may be mounted on the lead frame.

11 to 15 are cross-sectional views during manufacturing of the semiconductor device according to the present embodiment, and FIGS. 16 to 19 are plan views thereof. It should be noted that each cross-sectional view of FIGS. 11 to 15 is a cross-sectional view taken along the line I-I of FIGS. 16 to 19.

First, as shown in FIGS. 11 (a) and 16 (a), a metal plate 20 made of copper or a copper alloy is prepared.

The metal plate 20 has a first main surface 20a and a second main surface 20b that face each other, and the thickness thereof is about 50 μm to 500 μm.

A metal film of any one of gold, platinum, palladium, nickel, iron-nickel alloy, and cobalt may be formed on these main surfaces 20a and 20b.

As shown in FIG. 16A, the metal plate 20 has a long shape in a plan view and includes a plurality of rectangular product areas R. The product area R is an area that is later separated into products. Subsequent FIGS. 16 (b) to 19 (b) correspond to enlarged plan views of the product area R.

A rectangular outer frame 20z including each product area R is provided outside the product area R.

Next, as shown in FIGS. 11B and 16B, a photoresist is applied to the first main surface 20a of the metal plate 20, and the photoresist is exposed and developed to form a first resist layer 21. To do. Then, in the same manner as this, the second resist layer 22 is formed on the second main surface 20b.

Subsequently, as shown in FIGS. 12 (a) and 17 (a), the metal plate 20 is wet-etched from the front and back surfaces of the resist layers 21 and 22 as masks to bond the metal plate 20 to the die pad 20c. It is divided into a pad 20d. As an example, the die pad 20c and the bonding pad 20d are formed in a rectangular shape in a plan view.

Further, in the region where the second resist layer 22 is not formed on the second main surface 20b, the stepped portion 20x is formed by this wet etching.

The etching solution used in this wet etching is not particularly limited, but in the present embodiment, an aqueous ferric chloride solution is used as the etching solution.

After that, as shown in FIGS. 12 (b) and 17 (b), each of the first resist layer 21 and the second resist layer 22 is removed.

As shown in FIG. 17B, a connecting portion 20y is provided on the peripheral edge of the die pad 20c. The connecting portion 20y is a member that connects the die pads 20c in the adjacent product area R (see FIG. 16A), whereby the metal plate 20 is subjected to various processes in a state where the die pads 20c are connected to each other. be able to.

Similarly, a connecting portion 20y for connecting the bonding pads 20d in the adjacent product region R is also provided on the peripheral edge of the bonding pad 20d.

In the product area adjacent to the outer frame 20z (see FIG. 16A), each connecting portion 20y is connected to the outer frame 20z.

Next, as shown in FIG. 13A, a titanium oxide polymer film 5 is formed on the surfaces of the die pad 20c and the bonding pad 20d to a thickness of about 5 nm to 50 nm according to the flowchart of FIG.

The material of the polymer film 5 is not limited to the titanium oxide polymer. For example, by using a zirconium chelate in step S6 of FIG. 2, a polymer film 5 containing a polymer of zirconium oxide may be formed.

Subsequently, as shown in FIG. 13B, while using an aqueous solution of silver-potassium cyanide having a concentration of 80 g / liter to 200 g / liter as the silver plating solution, the silver film 6 is placed on the polymer film 5 by an electroplating method. Is formed to a thickness of about 1 μm to 8 μm.

In addition, potassium cyanide, dipotassium hydrogen phosphate, and boric acid may be added to the silver plating solution. In that case, the concentration of potassium cyanide may be 0 g / liter to 50 g / liter, the concentration of dipotassium hydrogen phosphate may be 0 g / liter to 100 g / liter, and the concentration of boric acid may be 0 g / liter to 40 g / liter.

However, since it is difficult to control the concentration of the brighteners shown in Table 1, none of the brighteners shown in Table 1 is added to this silver plating solution.

By forming the polymerized film 5 in advance on the base of the silver film 6 without adding a brightener in this way, the unevenness on the surface of the silver film 6 can be made finer as described above, and the silver film 6 can be glossy. A rich silver film 6 can be formed.

Further, as described above, since the polymer film 5 also functions as a copper diffusion prevention film, the polymer film 5 can prevent the copper of the metal plate 20 from diffusing into the silver film 6.

Next, as shown in FIGS. 14A and 18A, the thermosetting resin is supplied to both sides of the metal plate 20 by transfer molding, and then the thermosetting resin is thermally cured to form the resin portion 25. And.

In this example, an opening 25a is formed in the resin portion 25 on the first main surface 20a, and each of the die pad 20c and the bonding pad 20d is exposed from the opening 25a. The side surface 25x of the opening 25a serves as a reflector that reflects the light output by the light emitting element mounted on the die pad 20c later.

In this example, a thermosetting epoxy resin to which titanium oxide is added as a white pigment is used as the material of the resin portion 25 to make the color of the resin portion 25 white, thereby increasing the reflectance of light on the side surface 25x. ..

The white pigment is not limited to titanium oxide, and any one of alumina, magnesium oxide, antimony oxide, and zirconium oxide may be used as the white pigment. Further, inorganic hollow particles such as sodium silicate glass, aluminum silicate glass, sodium borosilicate glass, and silas may be used as the white pigment.

Further, the material of the resin portion 25 is not limited to the epoxy resin, and the resin portion 25 may be formed of any thermosetting resin such as a silicone resin, a urethane resin, a cyanate resin, and a fluororesin.

The step portion 20x is embedded in the resin portion 25, and the die pad 20c and the bonding pad 20d on the second main surface 20b side are exposed so as to be flush with the resin portion 25.

By the steps up to this point, the basic structure of the lead frame 30 according to the present embodiment is completed.

In the lead frame 30, the metal plate 20 functions as the lead frame main body.

In this example, the resin portion 25 is provided on the metal plate 20, but in some cases, the step of FIG. 14A may be omitted and the resin portion 25 may be omitted. In this case, the lead frame 30 is formed only from the metal plate 20 which is the lead frame main body.

After that, the process moves to the process of mounting the semiconductor element on the lead frame 30.

First, as shown in FIGS. 14 (b) and 18 (b), the semiconductor element 32 is fixed onto the die pad 20c via the conductive adhesive 31. In this example, a light emitting element such as an LED is used as the semiconductor element 32, and the back surface 32b of the semiconductor element 32 is fixed to the die pad 20c.

The back surface 32b of the semiconductor element 32 is a ground electrode, and the ground electrode and the die pad 20c are electrically connected via the conductive adhesive 31.

After that, the bonding pad 20d and the semiconductor element 32 are connected by wire bonding with a metal wire 33. As the metal wire 33, a gold wire is used here.

At this time, in the present embodiment, since the unevenness of the surface of the silver film 6 is miniaturized by the action of the polymerized film 5, the connection reliability between the end portion 33a of the metal wire 33 and the silver film 6 is improved.

Further, since the copper film 20 of the metal plate 20 can be prevented from diffusing into the silver film 6, the adhesive force between the metal wire 33 and the silver film 6 is lowered due to the copper diffused in the silver film 6. Can be prevented from doing so.

Next, as shown in FIGS. 15A and 19A, the opening 25a of the resin portion 25 is filled with the sealing resin 34, and the sealing resin 34 protects the semiconductor element 32 and the metal wire 33. To do.

As described above, since the light emitting element is used as the semiconductor element 32 in the present embodiment, the transparent resin that transmits the light emitted from the semiconductor element 32 is used as the sealing resin 34, and the sealing resin 34 transmits the light. Do not interfere.

Examples of such transparent resins include silicone resins and acrylic resins. If the transmission of light is not hindered, a translucent resin may be used as the sealing resin 34.

Further, a phosphor or an inorganic filler that diffuses light may be added to the sealing resin 34.

Next, as shown in FIGS. 15 (b) and 19 (b), the metal plate 20 and the resin portion 25 are cut along the cutting line L to obtain a plurality of semiconductor devices 40 according to the present embodiment. ..

This completes the basic steps of the semiconductor device manufacturing method according to the present embodiment.

FIG. 20 is a plan view of the semiconductor device 40 as viewed from the second main surface 20b side of the metal plate 20.

As shown in FIG. 20, the bonding pad 20d exposed from the resin portion 25 functions as a lead for external connection, and the die pad 20c also functions as an external connection terminal, so that the semiconductor device 40 does not work through these external connection terminals. It is connected to the wiring board shown in the figure.

In this example, the resin portion 25 is formed on the metal plate 20, but the resin portion 25 may be omitted as described above. In this case, after the semiconductor element 32 is fixed to the die pad 20c, the resin portion 25 and the portion corresponding to the sealing resin 34 may be sealed with the sealing resin.

According to the present embodiment described above, in order to form the silver film 6 on the polymer film 5 of titanium oxide or zirconium oxide in the step of FIG. 13B, a brightener is added to the silver plating solution of the silver film 6. Even if this is not done, the surface irregularities of the silver film 6 can be made finer.

Therefore, it is possible to eliminate the burden of controlling the concentration of the brightener in the silver plating solution, and the fine unevenness of the silver film 6 provides the adhesion between the silver film 6 and the metal wire 33 (see FIG. 15B). Can be improved.

Further, since the polymerized film 5 also functions as a diffusion prevention film for preventing the copper of the metal plate 20 from diffusing into the silver film 6, the copper of the metal plate 20 is less likely to diffuse into the silver film 6, and the copper As a result, it is possible to prevent the adhesion between the silver film 6 and the metal wire 33 from being lowered.

Moreover, when the light emitting element is used as the semiconductor element 32, the light emitted from the semiconductor element 32 can be efficiently reflected by the silver film 6 whose surface irregularities are miniaturized and the reflectance is improved. It is also possible to increase the amount of light obtained by the semiconductor device 40.

1 ... Copper plate, 2 ... Container, 3 ... Solution, 4 ... Coating film, 5 ... Polymerized film, 6 ... Silver film, 20 ... Metal plate, 20a ... First main surface, 20b ... Second main surface, 20c ... Die pad, 20d ... Bonding pad, 20x ... Stepped part, 20y ... Connecting part, 21 ... First resist layer, 22 ... Second resist layer, 25 ... Resin part, 25 ... Opening, 25x ... Side surface, 30 ... Lead frame , 31 ... Conductive adhesive, 32 ... Semiconductor element, 32b ... Back surface, 33 ... Metal wire, 33a ... End, 34 ... Encapsulating resin, 40 ... Semiconductor device.

Claims (8)

With a metal plate
A polymer film formed on the surface of the metal plate and containing a polymer of either titanium oxide or zirconium oxide,
The silver film formed on the polymerized film and
Lead frame with. The lead frame according to claim 1, wherein the metal plate has a die pad on which a semiconductor element is mounted and a bonding pad to which a metal wire connected to the semiconductor element is connected. Further having a resin portion formed on the metal plate and having an opening in which each of the die pad and the bonding pad is exposed.
The lead frame according to claim 2, wherein the semiconductor element is a light emitting element that emits light, and the side surface of the opening is a reflector that reflects the light. A lead frame having a metal plate, a polymer film formed on the surface of the metal plate and containing a polymer of either titanium oxide or zirconium oxide, and a silver film formed on the polymer film.
The semiconductor element mounted on the lead frame and
A metal wire connected to each of the semiconductor element and the lead frame,
Semiconductor device with. The process of forming a polymer film of either titanium oxide or zirconium oxide on the surface of the metal plate,
The step of forming a silver film on the polymerized film by a plating method and
A method for manufacturing a lead frame having. The step of forming the polymerized film is
A step of forming a coating film of a solution of a titanium chelate, a titanium oligomer, or a zirconium chelate on the surface of the metal plate.
The method for producing a lead frame according to claim 5, further comprising a step of forming the polymerized film by heating and polymerizing the coating film. The method for manufacturing a lead frame according to claim 6, wherein the step of heating the coating film is performed in an atmosphere of an inert gas. The method for producing a lead frame according to any one of claims 5 to 7, wherein in the step of forming the silver film, the silver film is formed by using a plating solution from which the brightener has been removed. ..