JPH1117097A - Lead frame and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device superior in adhesiveness by sealing a copper material having a copper alloy layer containing a specified amount of silicon atoms for the thickness of a specified range on a surface layer with the hardening object of an epoxy resin composition constituted of an epoxy resin, hardener and inorganic filler. SOLUTION: The lead frame 2 is formed of the copper material and the copper alloy layer containing 8-50 atom % of the silicon atoms for the thickness of 10-10000 angstroms on the surface layer of the copper material. A semiconductor element 1 is adhered to the lead frame 2 by the die bonding agent 3 of solder and silver paste and it is wire-bonded to an arbitrary circuit by wire 4. The lead frame is sealed with the hardening object 5 of epoxy resin composition containing epoxy resin, hardener and inorganic filler. Thus, the semiconductor device where adhesiveness with epoxy resin composition is improved can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame of a semiconductor device package having strong adhesion to a sealing resin and a highly reliable semiconductor device using the lead frame.

[0002]

2. Description of the Related Art In recent years,
In the semiconductor industry, resin-sealed diodes, transistors, ICs, LSIs, and super LSIs have become mainstream. Epoxy resin as a sealing resin is generally superior in moldability, adhesiveness, electrical properties, mechanical properties, moisture resistance, etc. as compared with other thermosetting resins, so semiconductor devices are sealed with an epoxy resin composition. There are many things to do.

In recent years, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly. On the other hand, package external dimensions have been reduced in thickness in response to demands for smaller and lighter electronic devices. Further, in the method of attaching a semiconductor component to a circuit board, the surface mounting of the semiconductor component has been widely performed due to the high density of components on the substrate and the thinning of the substrate.

When a semiconductor device is surface-mounted, generally, a method of immersing the entire semiconductor device in a solder bath or passing the semiconductor device through a high-temperature zone where solder is melted is used. If the adhesiveness between the sealing resin and the frame is low due to the thermal shock at that time, the interface is peeled off or cracks are generated in the sealing resin layer, and the reliability of the semiconductor device is reduced. There was a problem of being damaged.

[0005] For this reason, various improvements have been proposed for epoxy resin compositions for encapsulating semiconductor devices. However, almost all proposals have been made to improve the semiconductor devices to be encapsulated, particularly from the viewpoint of the material of the lead frame. Absent.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a lead frame having excellent adhesion to a sealing resin, particularly an epoxy resin, and a semiconductor device in which the lead frame is sealed with a cured product of an epoxy resin composition.

[0007]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventor has found that the surface layer has 8 to 50 silicon atoms with a thickness of 10 to 1000 angstroms. Semiconductor device having excellent adhesion by using a copper material having a copper alloy layer containing 0.1% by weight for a lead frame and sealing with a cured product of an epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler. And found that the present invention can be obtained.

That is, the present invention is characterized in that (1) a copper alloy layer formed of a copper material and having a surface layer of the copper material and having a thickness of 10 to 1000 angstroms and containing 8 to 50 atomic% of silicon atoms. (2) a lead frame formed of a copper material and having a copper alloy layer containing 8 to 50 atomic% of silicon atoms having a thickness of 10 to 1000 angstroms on a surface layer of the copper material; A semiconductor device characterized by being sealed with a cured product of an epoxy resin composition containing a curing agent and an inorganic filler.

Hereinafter, the present invention will be described in more detail.
The lead frame of the present invention having excellent resin sealing properties is based on copper. Preferably, it is a copper alloy containing 0.01 to 5 atomic% of silicon atoms. More preferably, the copper substrate is a copper alloy containing 0.03 to 3 atomic% of silicon atoms.

The lead frame of the present invention is formed of the above copper material, and has a copper alloy layer having a thickness of 10 to 1000 angstroms and containing 8 to 50 atomic% of silicon atoms on its surface. The copper alloy layer containing 8 to 50 atomic% of silicon atoms in the surface layer of this copper lead frame material can be obtained by doping pure copper or copper alloy containing no silicon atoms into a liquid of metallic silicon, but commercially available Cu-Ni- A copper material containing 0.01 to 5 atomic% of silicon atoms, such as a Si (Corson-based) copper alloy, is subjected to a reduction treatment condition in which a normal metal annealing treatment is performed, and a semiconductor element is soldered. It can be easily obtained by passing the conditions for reduction treatment. OMCL is a commercially available silicon-containing copper material.
-1 (manufactured by Mitsubishi Shindoh), KLF-1 (manufactured by Kobe Steel),
KLF-116 (manufactured by Kobe Steel), KLF-125 (manufactured by Kobe Steel), NK164 (manufactured by Nippon Mining), C
-7025 (manufactured by Ohrin Plus Co., Ltd.) and the like.

The conditions of the reduction treatment are as follows: by performing the treatment at a temperature of 100 to 600 ° C. in the presence of an atmosphere gas having a hydrogen content of 0.5% by volume or more, the surface of the copper material can be easily reduced to 10 to 10
A layer of copper alloy containing 8 to 50 atomic% silicon atoms with a thickness of 00 Å can be formed. The time of the reduction treatment is 30 seconds to 2 hours, more preferably 1 minute to 1 hour under the above conditions. If the time is less than 30 seconds, a sufficient reduction treatment cannot be performed. If the time exceeds 2 hours, the silicon atom concentration in the surface layer becomes too high, and the performance as a copper material is reduced. The conditions for performing the reduction treatment are as follows: an atmosphere gas having a hydrogen content of 0.5% by volume or more and a temperature of 100 to 600 ° C. for 30 seconds to 2 hours.
By performing the time reduction treatment, the surface layer of the copper material is covered with a copper alloy layer containing at least 8 atomic% of silicon atoms for at least 10 angstroms from the surface.

8 to 50 atomic% of silicon atoms in the surface layer of the copper material
The thickness of the copper alloy layer is at least 1 mm from the surface of the copper material surface layer.
0 Angstroms is required. If the thickness is less than 10 angstroms, the adhesiveness of the resin when the resin is sealed is not sufficient. Preferably, it is at least 25 angstroms from the surface, more preferably at least 50 angstroms. Further, since the surface layer of the copper alloy layer containing 8 to 50 atomic% of silicon atoms is an alloy layer for improving the adhesiveness of the resin when the resin is sealed, it is not necessary to be thicker than 1000 angstroms.

If the amount of silicon atoms in the copper alloy layer covering the copper material surface and containing 8 to 50 atomic% of silicon atoms is less than 8 atomic%, the adhesion of the resin when resin is sealed is not sufficient. Further, a copper alloy layer containing more than 50 atomic% lowers the performance (electrical conductivity and thermal conductivity) as a copper material. Preferably, the copper alloy layer has a silicon atom content of 10 to 40 at%, more preferably 12 to 30 at%.

The copper alloy layer containing 8 to 50 atomic% of silicon atoms in the surface layer does not necessarily need to have a uniform silicon atom content, and may have a lower silicon atom content as it is closer to the center than the surface. However, at least up to 10 Å from the surface, one silicon atom
It is preferable to contain 0 atomic% or more.

In the semiconductor device of the present invention, the semiconductor element is bonded to the above-mentioned lead frame with a die bonding agent such as solder or silver paste, and then wire-bonded to an arbitrary circuit. It is sealed with a cured product of an epoxy resin composition for semiconductor sealing containing a filler as a main component, and is, for example, shown in FIG.

Here, in FIG. 1, 1 is a semiconductor element, 2
Is a lead frame, 3 is a die bonding agent, 4 is a wire, and 5 is a cured product of an epoxy resin composition.

The epoxy resin constituting the epoxy resin composition of the present invention may be any epoxy resin having at least two epoxy groups in one molecule, and specifically, a bisphenol A type epoxy resin ,
Bisphenol type epoxy resin such as bisphenol F type epoxy resin, phenol novolak type epoxy resin,
Novolak type epoxy resins such as cresol novolak type epoxy resin, triphenol alkane type epoxy resins such as triphenol methane type epoxy resin and polymers thereof, biphenyl type epoxy resin, dicyclopentadiene-phenol novolak type epoxy resin, phenol aralkyl type epoxy Resins, naphthalene ring-containing epoxy resins, glycidyl epoxy resins, and the like can be used.

The use of these epoxy resins is not necessarily limited to one type, and two or more types may be mixed and compounded.

The curing agent is not particularly limited, and can be appropriately selected depending on the epoxy resin used. Examples thereof include amine curing agents, acid anhydride curing agents, and phenolic hydroxyl groups such as phenol novolak. And various phenolic resin curing agents having at least one of the above. Among them, a phenolic resin curing agent is more desirable and more preferably used in view of moldability and low humidity of the composition. Specific examples of the phenol resin curing agent include novolak type phenol resins such as phenol novolak resin and cresol novolak resin, bisphenol type resins such as bisphenol A and bisphenol F, triphenol alkane type resins such as triphenol methane, and phenol aralkyl. Examples thereof include a resin, a naphthalene ring-containing phenol resin, a cyclopentadiene-containing phenol resin, a terpene ring-containing phenol resin, and a biphenyl-type resin. The compounding amount of the curing agent is an amount capable of curing the epoxy resin, and can be a commonly used amount. Is preferably mixed in a molar ratio of 1: 0.5 to 1: 1.5.
30 to 120 parts by weight, preferably 4 parts by weight, per 100 parts by weight
0 to 70 parts by weight.

In order to accelerate the reaction between the epoxy resin and the curing agent, it is desirable to incorporate various curing accelerators, for example, imidazoles, tertiary amines, phosphine compounds, cycloamidine compounds and the like. The amount is not particularly limited, but is usually 0.05 to
It is preferably 1% by weight.

Further, in the present invention, a silicone polymer may be blended in the composition for the purpose of reducing the stress of the cured product. When a silicone-based polymer is blended, the occurrence of package cracks in a thermal shock test of the cured product can be significantly reduced. Examples of the silicone polymer include silicone oils having a functional group such as an alkenyl group such as an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a hydrosilyl group (Si-H group), a vinyl group and an allyl group (linear chain). , Cyclic and branched organopolysiloxanes), silicone resins (trifunctional and / or
Or a three-dimensional network structure containing tetrafunctional siloxane units), silicone rubber (organopolysiloxane crosslinked elastic body), and these silicone polymers (for example,
A linear diorganopolysiloxane having the above functional group in the molecule) and an organic polymer such as a substituted or unsubstituted novolac phenol resin or an epoxy resin having a functional group such as an alkenyl group in the molecule. Can be mentioned.

The amount of the silicone polymer to be added is not particularly limited, but is usually preferably 1 to 50 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.

Further, various known inorganic fillers are used in the composition used in the present invention. As the filler, those which are usually compounded in an epoxy resin composition can be used. Specifically, crystalline silica, fused silica, aluminum nitride, silicon nitride, silicon carbide, alumina, boron nitride, titanium oxide, glass fiber and the like can be mentioned. Among them, fused silica is preferable.

The average particle size and shape of these inorganic fillers are not particularly limited, but the average particle size (for example, as a weight average value by a method such as a laser diffraction method) is usually 3 to 30.
μm, particularly preferably 5 to 20 μm, and a spherical one is preferably used in order to increase the packing and reduce the stress on the chip surface. In order to increase the bonding strength between the resin and the surface of the inorganic filler, it is necessary to use a surface treatment that has been previously performed with a coupling agent such as a silane coupling agent or a titanate coupling agent. It is preferable from the viewpoint of improving crack resistance.

The above-mentioned inorganic fillers may be used alone or in combination of two or more. The amount of the inorganic filler is not particularly limited.
It is preferably in the range of 95% by weight, especially 75 to 92% by weight. If the amount of the filler is less than 70% by weight, the expansion coefficient of the obtained cured product becomes large, so that the stress characteristics may be deteriorated. If it exceeds 95% by weight, the melt viscosity at the time of molding becomes high. In some cases, voids, unfilled portions, etc. may occur due to too much.

The composition used in the present invention may further contain various additives, if necessary. For example, waxes such as carnauba wax, releasing agents such as fatty acids such as stearic acid and metal salts thereof, and organic compounds. Flexible agents such as rubbers, pigments such as carbon black, cobalt blue, red iron oxide, flame retardants such as antimony oxide and halogen compounds, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, aging One or more kinds of inhibitors and other additives can be blended.

In the epoxy resin composition used in the present invention, predetermined amounts of the above-mentioned components are uniformly stirred and mixed, and 70 to 9
It can be obtained by a method such as kneading, cooling and pulverizing with a kneader, roll, extruded mixer or the like heated to 5 ° C., but a melt mixing method using an extrusion kneader is particularly preferably used. . There is no particular limitation on the order of mixing the components.

Here, when sealing the semiconductor device,
Conventional molding methods such as transfer molding and casting can be employed. In this case, the molding temperature of the epoxy resin composition is 150 to 180
Post-curing can be performed at 150 to 200 ° C. for about 2 to 20 hours. As described above, since the semiconductor device of the present invention has good adhesiveness, it can be suitably used as a semiconductor device such as an IC, an LSI, a transistor, and a diode mounted on the lead frame.

[0029]

According to the present invention, the surface of the copper material has a thickness of 10-1.
8 to 50 Angstroms thick silicon atom
By using a lead frame including a copper alloy layer containing at least atomic%, a semiconductor device with improved adhesion to an epoxy resin composition can be provided.

[0030]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Examples and Comparative Examples] Kolson copper material KLF
Hot rolling, annealing, grinding, cold rolling using -1 (manufactured by Kobe Steel, Ni content 3.4 at%, Si content 1.5 at%, Zn content 0.3 at%) Through the process of K
An LF-1 copper frame was obtained (referred to as frame G).

A DX gas containing 7.0 vol% of CO ₂ , CO gas containing 8.2 vol% of hydrogen gas,
10.2 vol%, CH ₄ 0.5% by volume, N ₂ 74 vol%)
Under an atmosphere of 350 ° C. for 30 minutes (referred to as frame A).

Similarly, a reduction treatment was performed at 250 ° C. for 60 minutes in an atmosphere of AX gas (25% by volume of N ₂ ) containing 75% by volume of a KLF-1 copper frame in hydrogen gas (Frame B).
And).

Similarly, a reduction treatment was performed at 350 ° C. for 15 minutes in an atmosphere of an AX gas (25% by volume of N ₂ ) containing a KLF-1 copper frame of 75% by volume of hydrogen gas (referred to as a frame C).

Similarly, a reduction treatment was performed at 350 ° C. for 60 minutes in an atmosphere of AX gas (25% by volume of N ₂ ) containing 75% by volume of a KLF-1 copper frame in hydrogen gas (Frame D).
And).

Similarly, a reduction treatment was performed at 500 ° C. for 1 minute in an atmosphere of AX gas (25% by volume of N ₂ ) containing 75% by volume of a KLF-1 copper frame in a hydrogen gas (referred to as frame E).

Hot rolling was carried out using Corson copper material NK164 (manufactured by Nippon Mining Co., Ni content 1.7 at%, Si content 0.9 at%, Zn content 0.4 at%). Through the processes of annealing, grinding and cold rolling, NK16
A 4 copper frame was obtained (referred to as frame H).

The NK164 copper frame was supplied with hydrogen gas 7
Under the atmosphere of AX gas (25% by volume of N ₂ ) containing 5% by volume,
A reduction treatment was performed at 400 ° C. for 30 minutes (referred to as frame F).

Next, when the surfaces of these copper frames A to F were subjected to a surface analysis using an X-ray wide scan spectrum, they contained 10 atom% or more of silicon atoms. Table 1 shows the results.

Further, this copper material was 25
The angstrom surface was removed, and the surface was analyzed using an X-ray wide scan spectrum. The results are also shown in Table 1.

Using the above copper lead frame, the adhesion to the cured product of the epoxy resin composition was measured by the following method. The results are also shown in Table 1. Epoxy resin composition The following were used as the epoxy resin composition. In the following composition, “parts” means “parts by weight”.

An epoxy equivalent of 198, a softening temperature of 80 ° C., 51 parts of epoxidized cresol novolak resin, an epoxy equivalent of 280, 6 parts of a brominated epoxidized phenol novolak resin, 60 parts of a compound represented by the following formula (1) and the following formula (2) 10 parts of a reaction product with 40 parts of a compound represented by the formula:
450 parts of fused silica (average particle size 15 μm), 10 parts of antimony trioxide, 1.2 parts of carnauba wax, 1.0 part of γ-glycidoxypropyltrimethoxysilane, 1.0 part of carbon black and phenol equivalent weight 110, softening 33 parts of a phenol novolak resin at a temperature of 90 ° C. and 0.65 parts of triphenylphosphine were melt-mixed for 5 minutes using a mixing roll at an temperature of 80 ° C., then taken out into a sheet, and cooled to obtain an epoxy resin composition.

[0043]

Embedded image

[0044] From adhesion the copper frame of the resin cut specimens for the resin adhesion evaluation test (20 × 20 × 0.3mm), this by using the epoxy resin composition of FIG. 2 (A), A resin block having the shape shown in (B) was formed by molding at 175 ° C. for 2 minutes. The obtained resin block was post-cured at 180 ° C. for 4 hours, and the shear adhesive strength was measured. In the figure, 11 is a lead frame, 12 is a resin block (3.5 mm in diameter at the bottom).
68 mm, top surface diameter 3 mm, height 3 mm). Adhesion after moisture absorption (IR reflow resistance) 14 × 20 × 1.2 mm 64 with the above copper lead frame
Create a PIN-QFP frame and make it 8.0 × 10.0 ×
A silicon chip having a size of 0.3 mm is adhered with a silver paste, and an epoxy resin composition is added thereto at 175 ° C. and 70 k.
Molding was performed at gf / cm ² for 2 minutes, and post-curing was performed at 180 ° C. for 4 hours. 85 ° C x 85
After leaving it in a% Rh atmosphere for 168 hours to perform a moisture absorption process, it was passed through an infrared reflow furnace at 240 ° C., and the number of cracked packages at this time was examined (n =
8).

[0045]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an example of a semiconductor device.

FIG. 2 shows a resin block, wherein (A) is a plan view and (B)
FIG. 3 is a cross-sectional view of a state where a resin block is bonded to a frame.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor element 2 lead frame 3 die bonding agent 4 wire 5 cured product of epoxy resin composition 11 frame 12 resin block

Continued on the front page (72) Inventor Naoya Noguchi 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Isobe Plant

Claims (2)

[Claims] Claims: 1. A copper material formed on a surface layer of a copper material,
A lead frame having a copper alloy layer having a thickness of 10 to 1000 angstroms and containing 8 to 50 atomic% of silicon atoms. 2. Formed by a copper material, a surface layer of the copper material,
A lead frame having a copper alloy layer having a thickness of 10 to 1000 angstroms and containing 8 to 50 atomic% of silicon atoms is sealed with a cured product of an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler. A semiconductor device characterized by being stopped.