JPH06169051A - Lead frame and manufacture thereof and semiconductor package - Google Patents

Abstract

PURPOSE:To provide a lead frame, which is intended for realizing a surface mounting type high-speed LSI package that is light and can be provided at a low cost, can provide the fine pitch of inner leads, can cope with multiple pins and has the excellent heat dissipation property, low power-supply noise characteristics and wire bonding characteristics, and to provide the manufacturing method of the lead frame and the semiconductor package using this lead frame. CONSTITUTION:The layers having the following constitutions are sequentially laminated, and a unitary body is formed. A grounding layer 1 has a plurality of protruding parts 2 for leads at the peripheral part. A heat resisting insulating epoxy resin layer 3 is provided. A square-frame shaped power supply part layer 7 is separated from each lead 5 and connected to power supply leads 6. The layer 7 is formed at the space part at the inside of the tips of the leads 5 in a lead frame layer 4. An insulating material layer 8 comprises a thin film of heat-resisting insulating epoxy resin or ceramic, which is formed at the required part other than the central part of the square- frame shaped power supply part layer. A signal wiring layer 9 comprises an Al thin film wiring or a Cu thin film wiring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame for providing a semiconductor package capable of coping with an increase in the number of pins, excellent in high speed, heat dissipation, and low power supply noise characteristics. A lead frame layer having a rectangular frame-shaped power supply layer formed in the space of the above is laminated via a heat-resistant insulating resin layer, and a heat-resistant epoxy insulating resin or ceramic thin film is formed on the lead frame layer and the power supply layer. It has a multi-layered structure in which the inner leads are formed by the filmed Al thin film wiring, and the inner leads have a fine pitch and can support a large number of pins, and have excellent heat dissipation and low power noise characteristics.
In addition, the present invention relates to a lead frame in which wire bonding characteristics are remarkably improved, a manufacturing method thereof, and a semiconductor package using the lead frame.

[0002]

2. Description of the Related Art In recent years, the integration of semiconductor devices has rapidly increased, and along with this, there has been a demand for a lead frame having a large number of pins and a lead pitch narrowing. Surface mount type QFP (Quad
Flat Package) is used in various semiconductor devices.

In addition, the semiconductor element has become smaller and lighter,
High capacity and high speed operation are also required, and ceramic PGA (Pin Gr
idArray) was used. This ceramic P
Compared with QFP, GA has features that it is easy to increase the number of pins, has excellent heat dissipation, and has a multi-layered structure that facilitates obtaining low noise characteristics.

Today's laptop computers are becoming faster and larger in capacity, and due to the demand for high-speed LSIs to be smaller and lighter, surface mount type lightweight and inexpensive plastic QFPs are used.
Is required. However, conventional plastic QFP
The single-layer type lead frame for use has been miniaturized in order to cope with the above-mentioned increase in the number of pins, but miniaturization of the lead increases the resistance of the lead, which causes signal distortion, There is a problem that the response of the semiconductor element is deteriorated. In addition, the heat dissipation is about 1 W even with a plastic QFP using a single-layer Cu lead frame with good thermal conductivity, and the power consumption is 2-3 W for high-speed MPU (MicroP
There was a problem that the processing unit could not be installed.

In a conventional single-layer type lead frame for a plastic QFP, a required wiring pattern is formed on a metal strip by pressing or the like, but the metal strip is thinned by downsizing of a semiconductor device. Therefore, there is a limit to miniaturization of leads due to problems such as strength. Therefore,
Providing a stage on which a semiconductor element is mounted and a lead frame separately, and supporting the stage on the lead frame via an insulator reduces package damage, improves heat dissipation, and increases the number of pins (special feature). Kaisho 63-3
18763).

Further, by laminating a power source layer or a ground layer made of a flat metal plate and a lead frame via an insulating double-sided adhesive film or the like, it is possible to increase the area of the power source and the ground and improve the heat dissipation. (Japanese Patent Laid-Open No. 63-24
6851).

Further, a common lead for ground and a lead frame are laminated, and a common lead for power supply is provided in an inner space portion of a large number of leads arranged in the lead frame,
It is proposed to reduce the number of power supply leads and ground leads among a large number of leads to increase the number of pins (Japanese Patent Laid-Open No. 1-931).
No. 56).

[0008]

The above-mentioned conventional multi-layer type lead frame achieves improved heat dissipation and more pins than the conventional single-layer type lead frame, but the lead tip pitch is There is a limit to the narrow pitch of about 0.3 mm, and it has not been possible to meet the demand for further increase in the number of pins. In addition, when the power supply layer or the ground layer and the lead frame are laminated and bonded, an insulating double-sided adhesive film such as polyimide having a small thickness and excellent in insulating effect is used, but the insulating double-sided adhesive film is a flexible material. Therefore, the bonding load of the wire bonder and the ultrasonic output are diverged to the base side, and the bonding strength of the wire and the uniformity of the bonding are deteriorated, which causes a problem of defective bonding. In any case, conventional multi-layer type lead frames have not been able to satisfy all of the high pin count, high heat dissipation, and low noise characteristics required for high-speed LSI.

The applicant used a low thermal expansion alloy for a cap enclosing a substrate and a chip as a metal package excellent in mechanical strength and heat dissipation, and applying a high melting point glass as an insulating layer of the substrate, A structure has been proposed (Japanese Patent Laid-Open No. 2-303052) in which the inner lead is arranged and formed of an Al or Cu thin film to facilitate the connection with the outer lead, and the substrate and the cap are integrated with a low melting point glass.

Further, the applicant has proposed, as a lead frame for providing a semiconductor package excellent in high pin count, high speed, high heat dissipation, and low noise characteristics, a rectangular frame in the space portion inside the tip of the ground plate layer and the lead. The lead frame layer on which the power supply layer is formed by glass welding with the glass thin film of the insulating layer, and the inner lead is formed by the Al thin film wiring formed on the lead frame layer and the power supply layer through the glass or ceramic thin film. A lead frame having a formed multilayer structure was proposed (Japanese Patent Application No. 3-246600).

However, the former metal package has an electromagnetic shielding effect and excellent heat dissipation, but satisfies all of the high pin count, high heat dissipation, and low noise characteristics required for high-speed LSI. However, it cannot be provided inexpensively. Further, both of the above proposals use glass such as high melting point glass or low melting point glass for the insulating layer. However, the glass is broken at the time of adhesion, or a photoresist film is formed on the glass in order to form Al thin film wiring. Developer used when
There is a problem that the glass is attacked by the stripping solution, water, etc., and the Al thin film forming the inner leads is attacked.

An object of the present invention is to provide a lead frame capable of realizing a semiconductor package for a high speed LSI, which has characteristics comparable to those of a ceramic PGA which is optimum for a high speed LSI, and which can be provided at a low cost in a surface mount type. Fine pitch of the inner leads is possible, it is possible to support a large number of pins, it has excellent heat dissipation and low power noise characteristics, and the wire bonding characteristics are remarkably improved, and its manufacturing method and the semiconductor package using this lead frame. It is intended to be provided.

[0013]

SUMMARY OF THE INVENTION According to the present invention, there is provided a grounding plate layer having a plurality of lead projections in a peripheral portion thereof, and a rectangular frame which is separated from each lead in a space portion inside the lead tip and is connected to a power supply lead. And a lead frame layer on which a heat-resistant insulating resin layer covering a part of the lead and the rectangular frame-shaped power supply layer is welded and laminated, and the protrusion of the ground plate layer and the lead frame layer are formed. A grounding lead is connected, and an Al thin film wiring or an insulating thin film made of a heat-resistant insulating resin thin film or a ceramics thin film is interposed on a predetermined portion of the lead frame layer excluding the central portion of the rectangular frame-shaped power supply layer. A lead frame is characterized in that a signal wiring layer made of Cu thin film wiring is formed to constitute an inner lead.

Further, according to the present invention, (1) a metal plate for grounding, which is formed so that a grounding plate layer having a required shape and having a plurality of protrusions on the peripheral portion thereof can be punched, is wire-bonded at least to a surface to be grounded with a chip. Forming a thin film for heat treatment, and further providing a heat-resistant insulating resin thin film on a required surface other than the surface to be grounded, or instead of forming a thin film for wire bonding on the surface to be grounded with at least the semiconductor chip, in advance. Using a grounding metal plate clad with a thin film,
A step of providing a heat-resistant insulating resin thin film on a required surface, and (2) a lead formed in a space inside the tip of the lead, separated from each lead and having a rectangular frame-shaped power supply layer connected to the power supply lead, and capable of being punched. On the metal plate for the frame, the wire bonding thin film is formed on the rectangular frame power supply part and the wire bonding planned surface, and the heat resistant insulating resin thin film or ceramic is formed on the required part except the central part of the rectangular frame power part layer. A step of providing a thin film, and (3) placing the lead frame metal plate on the grounding metal plate and adhering them together with a heat resistant insulating resin layer between the two, and then forming the heat resistant insulating resin thin film or Al thin film wiring or C on the ceramic thin film
A method of manufacturing a lead frame, comprising: forming a thin film wiring of u, providing an inner lead, and connecting a lead projection of a ground plate and a lead of a lead frame metal plate.

Further, the present invention is a semiconductor package, which is mainly composed of the lead frame having the above-mentioned structure and which is sealed with resin together with the semiconductor chip fixed to the ground plate layer. Further, the present invention is mainly composed of the lead frame having the above-mentioned structure, and the exposed surface of the ground plate layer is sealed with a heat-resistant insulating resin, and the semiconductor chip fixed to the ground plate and the metal cap encapsulating the inner lead are heat-resistant. It is a semiconductor package characterized by being sealed with an insulating resin.

Further, the present invention provides the lead frame, the manufacturing method thereof, and the semiconductor package as described above,
The above-mentioned heat-resistant insulating epoxy resin is a novolac epoxy resin 40% to 50%, and a filler 40% to 50% which is a mixture of barium sulfate and silica subjected to a coupling treatment in advance.
%, The pigment is 1% to 2%, and the solvent carbitol acetate is 8% to 9% as a main component as 100 parts, and 6 to 20 parts of an imidazole-based curing agent is prepared.

Preferred Embodiments of the Invention As a material of the lead frame layer having the rectangular frame-shaped power source portion used in the present invention and the ground plate layer having the protrusions, F
e-Ni alloys (42Ni-Fe etc.), Fe-Cr alloys (18Cr-Fe etc.), Fe-Ni-Cr alloys (42
Known low thermal expansion alloys such as Ni-6Cr-Fe) can be used. Also, in consideration of heat dissipation, C having good thermal conductivity
It is also possible to use a clad material of the above-mentioned low thermal expansion alloy in which u, Cu alloy or the like is disposed in the intermediate layer, for example, Invar / Cu / Invar, Kovar / Cu / Kovar, and in addition to the thermal expansion, the contact with the lead frame layer is taken into consideration. It is preferable that the ground plane layers are made of the same material. Further, the thicknesses of the lead frame layer and the ground plate layer are preferably 0.05 mm to 0.5 mm in consideration of miniaturization of the semiconductor package and heat dissipation.

A thin film for wire bonding is formed on the tip of the lead of the lead frame layer, the surface of the grounding plate layer to be grounded to the semiconductor chip, the rectangular frame-shaped power source layer of the lead frame layer, and the like. The material is A depending on the material of the planned bonding wire.
Wire bonding can be reliably performed by forming a metal or alloy film such as l or Cu by a vapor phase film forming method such as vapor deposition, or by providing an Au thin film such as Au plating on the formed Al or Cu thin film. . For example, when an Al bonding wire is used, an Al film is formed in advance on a predetermined wire bonding planned portion, and when an Au bonding wire is used, a Cu film is formed on the predetermined portion and then Au plating is performed. It is preferable to form the thin film for wire bonding by applying it. In particular, as a ground plate having a protrusion, Al or Cu may be formed on the entire surface or a part of the low thermal expansion alloy depending on the material of the bonding wire.
It is possible to omit the film forming step of the Al or Cu thin film at the position to be wire-bonded by using the material clad with or by plating the surface of the clad with Au.

Heat-Resistant Insulating Resin In the present invention, the heat-resistant insulative resin is used for adhesion and lamination of the ground plate layer and the lead frame layer and for insulation, a wire bonding thin film for the ground plate layer and the lead frame layer, and an Al thin film wiring or Thermal expansion with the lead frame is required because the bonding load during wire bonding between the signal wiring layer made of Cu thin film wiring and the semiconductor element and the underlayer divergence of ultrasonic output are required and heat resistance that can withstand the high temperature during bonding is required. A heat-resistant insulating epoxy resin having a small coefficient difference, high mechanical strength, excellent heat resistance and moisture resistance, and no elution of Na and Cl is desirable.

The heat-resistant insulating epoxy resin according to the present invention contains an aromatic ring or a chlorine ring in the main chain and increases the number of epoxy groups per molecule (multifunctionalization) to make the three-dimensional network structure denser, It is characterized by shortening the bridge point distance and improving heat resistance. As a specific component, novolac epoxy resin (epoxy equivalent 173 to 185, functional group number 2.4 to 3.6) 40% -40% to 50% and 40% to 50% filler composed of a mixture of precipitated barium sulfate and fine silica powder, which has been previously coupled with a coupling agent.
And pigment 1% to 2% and solvent carbitol acetate 8
% To 9% as the main component, and 6 to 20 parts of the imidazole-based curing agent is prepared.

In the heat-resistant insulating epoxy resin of the present invention, the novolac epoxy resin is a polyfunctional one having a large number of epoxy groups per molecule in order to improve the heat resistance of the heat-resistant insulating epoxy resin as described above. Is preferred.
The ratio of the novolac epoxy resin in the main component is
If it is less than 40%, the adhesive strength will decrease, and if it exceeds 50%, the heat resistance will decrease, so 40% to 50% is the preferred range.

In the heat-resistant insulating epoxy resin according to the present invention, it is necessary to add a filler made of a mixture of the precipitated precipitated barium sulfate and fine silica powder, which has been subjected to the coupling treatment, to the novolac epoxy resin because the coefficient of thermal expansion of the novolac epoxy resin is added. Matching to the ground plane layer and the lead frame layer, and because it has the effect of improving the heat resistance, further, by adding a filler, it is possible to concentrate the bonding load and ultrasonic output of the wire bonder at the time of wire bonding, This is because the wire bonding characteristics can be significantly improved.

The precipitated barium sulfate in the filler is
As an inorganic filler, it is effective in improving heat resistance, and it is preferable to perform a coupling treatment in advance in order to improve the adhesive force with the novolac epoxy resin. The particle size of the precipitated barium sulfate to be subjected to the coupling treatment is preferably 0.1 μm to 50 μm because the printability decreases when it is less than 0.1 μm and the heat resistance decreases when it exceeds 50 μm.

In the heat-resistant insulating epoxy resin according to the present invention, a silane coupling agent having a chemical structural formula represented by YRSiX ₃ is suitable as a coupling agent for coupling barium sulfate. X is a hydrolyzable group bonded to a silicon atom CL, OR, OCOR
Is equal, Y is an organic functional group CH ₂ = CH which reacts with the organic _{matrix, CH 2 = CCH 3 COO,} NH 2, NH 2 C 2
H ₄ NH, NH ₂ CONH, HS, CL, and those shown in Chemical formula 1 below.

[0025]

[Chemical 1]

As the silane coupling agent, γ-glycidoxypropyltrimethoxysilane (molecular weight 236.
1), γ-chloropropyltrimethoxysilane, β-
(3.4 epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane,
γ-ureidopropyltriethoxysilane and the like can be used. Since these silane coupling agents have both a portion X reactive with an inorganic substance and a portion Y highly reactive with an organic substance in the molecule, the adhesive force is remarkably improved. A titanium coupling agent or the like can also be used as the coupling agent.

Silica used in combination with the above-mentioned coupling-treated precipitated barium sulfate is added because it has an effect on heat resistance. Further, it is preferable that the powder is a fine powder having a particle diameter of 50 nm or less. The ratio of the mixture of the precipitated barium sulfate and silica in the main agent is 40% to 50.
%, Less than 40% is not preferable because heat resistance is deteriorated, and more than 50% is not preferable because printability is deteriorated.

As the organic pigment to be added to the main component, cyanine green having a particle size of about 2 μm, phthalocyanine blue, copper phthalocyanine and the like are preferable, and the addition amount thereof is taken into consideration in terms of heat resistance, chemical resistance and solvent resistance. 1% ~
Addition of 2% is preferred.

Further, as the solvent carbitol acetate, in addition to the solvent methyl carbitol, serfulv acetate, butyl cellosolve, cellosolve, etc. are preferable, and if the addition amount is less than 8%, the viscosity becomes high and the printability becomes poor. If it exceeds 9%, the viscosity is lowered and the printability is also lowered, which is not preferable. Therefore, addition of 8% to 9% is preferable. Furthermore, it is also effective to add a small amount of an antifoaming agent together with the above-mentioned pigment and the solvent methyl carbitol.

The curing agent added to the main agent is preferably an imidazole type curing agent, and the compounding amount of the main agent is 1
If it is less than 3 parts as 00 parts, the effect of heat resistance is poor and 2
If you exceed 0 copies, the pot life will be shortened, so 3 copies-2
0 part is preferable, and 6 to 20 parts is more preferable. Examples of the above-mentioned imidazole include imidazole, 2-
Methyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, 2-undecyl imidazole, 2-heptadecyl imidazole, 1-benzyl-2-methyl imidazole, 2-phenyl-4-methyl imidazole, 1-cyanoethyl -2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole,
1- (cyanoethylaminoethyl) -2-methylimidazole, N- (2-methylimidazolyl-1-ethyl)
-Urea, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 1-cyanoethyl-2-ethyl-4
-Methylimidazole trimellitate, 1-cyanoethyl-2-undecylimidazole trimellitate, 2.
4-diamino-6- (2'-methylimidazolyl-
(1 ′))-Ethyl-S-triazine, 2.4-diamino-6- (2′-undecylimidazolyl- (1 ′))
-Ethyl-S-triazine, 2.4-diamino-6-
(2'-ethyl-4'-methylimidazolyl-
(1 ′))-Ethyl-S-triazine, 1-dotecil-
2-methyl-3-benzylimidazolium chloride,
N, N'-bis- (2-methylimidazolyl-1-ethyl) -urea, N, N '-(2-methylimidazolyl-
(1) -Ethyl) -adipoyldiamide, 2.4-dialkylimidazole-5-dithiocarboxylic acid, 1.3-
Dibenzyl-2-methylimidazolium chloride, 2
-Phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4.5-dihydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4.5
-Di (cyanoethoxymethyl) imidazole, 2-methylimidazole-isocyanuric acid adduct, 2-phenylimidazole-isocyanuric acid adduct,
2.4-Diamino-6 (2'-methylimidazolyl-
(1) ') Ethyl-S-triazine-Isocyanuric acid adduct, 2-alkyl-4-formylimidazole, 2.4-dialkyl-5-formylimidazole and the like are preferable.

The heat-resistant insulating resin described above is a rectangular frame-shaped power source in which a ground plate layer having a plurality of lead projections in the peripheral portion and a space inside the tip of the lead are separated from the leads and connected to the power leads. The heat resistance, moisture resistance and mechanical strength are provided between the lead frame layer on which the partial layer is formed and between the lead frame layer and the signal wiring layer made of Al thin film wiring or Cu thin film wiring. Therefore, it is used as an adhesive for sealing when the packaging material is packaged with a metal cap or ceramics cap, and the bottom of the package when exposed with a metal cap or ceramics cap, that is, the exposed ground plane layer is exposed. It is also effective to adhere the entire surface for insulation. When the heat-resistant insulating resin is interposed between the ground plate layer and the lead frame layer, the thickness is less than 50 μm, the insulation is poor, and when it exceeds 200 μm, heat transfer from the lead frame layer to the ground plate layer is caused. 5 because it gets worse
The thickness is preferably 0 μm to 200 μm, more preferably about 100 μm.

As a method for fixing the heat-resistant insulating resin, a well-known technique can be adopted. For example, after the heat-resistant insulating resin is formed into a thin film with a required thickness and a required pattern by screen printing on a required portion of the ground plate layer, the heat-resistant insulating resin is fixed. The lead frame layer is attached to the grounding plate layer via the via and heated at a temperature of 80 ° C. to 90 ° C. for at least 1 hour or more, and then a temperature of 130 ° C. to 2
A hardening treatment of heating at 00 ° C. for at least 30 minutes or more is applied and fixed.

As the insulating material for the Al thin film wiring or the Cu thin film wiring, in addition to the above-mentioned heat resistant insulating resin, Al ₂
Ceramics such as O ₃ can be used, and Al ₂ O ₃
When used, Al ₂ O ₃ can be formed by a vapor phase film forming method such as sputtering or vapor deposition, and since the insulating layer is dense, it is preferable as the insulating layer formed on the lead frame layer. The thickness is preferably 3 μm to 20 μm, and has an advantage that the semiconductor package can be made thinner than the above heat-resistant insulating resin.

In the present invention, Al thin film wiring and Cu
The thin film wiring is processed by masking the insulating material layer attached on the lead frame layer and a predetermined position on the tip of the lead, and
l or Cu is vapor-deposited to form a film, and the mask material is removed to complete the thin film wiring. In addition, Al or Cu thin film is previously attached to the lead tip and the entire surface of the insulating material, or deposited by vapor deposition, and then etched. A thin film forming technique such as a method of removing an unnecessary portion by processing can be applied easily and accurately. The above Al or Cu thin film wiring has an advantage that a thin film forming technique such as vapor deposition or etching can be easily applied and wire bonding with a semiconductor element can be easily performed. The thickness of the Al or Cu thin film wiring may be appropriately determined depending on the number of leads and the like, but is preferably 3 μm to 20 μm in consideration of electrical characteristics such as responsiveness and distortion. When Au is used for the bonding wire, it is advisable to provide a thin film wiring made of Au plating or the like on the Cu thin film wiring.

Disclosure Based on the Drawings FIG. 1 is an exploded perspective view showing a laminated state of an embodiment of a lead frame according to the present invention. 2A to 2D are longitudinal explanatory views showing a manufacturing process of the lead frame according to the present invention. 3A shows a resin-sealed semiconductor package according to the present invention, and b shows a metal-cap-sealed semiconductor package. The structure and manufacturing method of the lead frame according to the present invention will be described in detail below with reference to FIGS. The lead frame according to the present invention, as shown in FIG. 1, will be described in order from the ground plate layer 1 having a plurality of lead projections 2 on the periphery thereof.
The lead frame layer 4 in which a rectangular frame-shaped power source layer 7 is formed in the space inside the tips of the leads 5 so as to be separated from each lead 5 and connected to the power source lead 6, and is required except for the central portion of the rectangular frame-shaped power source layer. Insulating material layer 8 consisting of heat-resistant insulating epoxy resin thin film or ceramics thin film formed on a portion, Al
Each layer of the signal wiring layer 9 made of thin film wiring or Cu thin film wiring is laminated and integrated by a manufacturing method described later.

The lead frame layer 4 in FIG. 1 shows an example having a frame portion for supporting the leads called a section bar and guide rail before the outer lead is punched and formed, and the following manufacturing method is required. An example of taking a plurality of strips will be shown. Further, the case where Al or Cu is used for the bonding wire will be described, and it is preferable that the thin film provided at the intended bonding position when Au is used for the wire is further provided with an Au film on the Cu film.

As shown in FIG. 2, first, a strip-shaped grounding plate made of a low thermal expansion alloy such as 42Ni-Fe alloy and having a required size is formed.
For example, after performing the required masking, a plurality of ground plate layers 1 are formed by etching, and after removing the masking,
Al thin film or Cu as a thin film for wire bonding
The thin film 10 is formed at least at a predetermined bonding position by, for example, sputtering or vapor deposition. The ground plate layer 1 is provided with a protrusion 2 at a predetermined peripheral position for connecting to the ground lead of the lead frame layer 4 by spot welding or the like. Further, the ground plate layer 1 can be formed by pressing instead of the etching method.

In order to omit the above-mentioned steps of sputtering and vapor deposition formation, the entire surface or a required portion of the low thermal expansion alloy is clad with Al or the like in advance, and then the ground plate layer 1 is formed by pressing or etching. You can also do it. Furthermore, the heat-resistant insulating epoxy resin layer 3 is formed on each ground plate layer 1 of the strip-shaped ground plate by, for example, screen printing technology.
Is deposited at a required position except the mounting position of the semiconductor chip.

Similarly, a strip-shaped lead frame substrate having a required size and made of a low thermal expansion alloy such as a 42Ni-Fe alloy is printed with a required pattern, developed, and then treated with an etching solution, as shown in FIG. A plurality of such lead frame layers 4 are formed. That is, the lead 5 on the substrate
And the power supply leads 6 are arranged as required, and the power supply leads 6 are separated from the respective leads 5 in the space inside the tips of the leads 5.
The rectangular frame-shaped power supply part layer 7 connected to is formed.

Further, an Al thin film or a Cu thin film 11 is formed as a wire bonding thin film on the lead frame layer 4 at a predetermined wire bonding position by sputtering or vapor deposition. Further, an insulating material layer 8 formed by depositing a heat-resistant insulating epoxy resin thin film made of the same material as the heat-resistant insulating epoxy resin layer 3 is provided by a screen printing technique, for example, on a required portion of the rectangular frame-shaped power source layer except the central portion. . When the insulating material layer 8 made of, for example, an Al ₂ O ₃ thin film is provided instead of the heat-resistant insulating epoxy resin thin film, it can be formed by sputtering, vapor deposition, or the like.

Next, a strip-shaped lead frame substrate is laid on the strip-shaped ground plate using a jig, and the heat-resistant insulating epoxy resin layer 3 is cured at the required temperature and time, so that the ground plate layer 1 and the lead frame. Layer 4 is laminated. After stacking, in order to form inner leads on the required positions of the leads on the lead frame layer 4 and on the insulating material layer 8, after masking a predetermined wiring pattern, Al or Cu is sputtered or vapor-deposited and masked again. By the method of removing the material, the signal wiring layer 9 made of Al thin film wiring or Cu thin film wiring is formed. In addition, the lead tip and the entire surface of the insulating layer 8 are previously A
Alternatively, it can be formed by a method in which an unnecessary portion is removed by an etching process after a 1 or Cu foil is attached or a film is formed by vapor deposition.

Then, the ground lead 2 of the ground plate layer 1 and the lead of the lead frame layer 4 are connected by means of spot welding or the like, whereby the lead frame 20 of the present invention is connected.
Can be obtained. After fixing the semiconductor chip 21 to the ground plate layer 1 in the central space of the obtained lead frame 20 with a brazing material or an adhesive, a rectangular frame-shaped power supply layer 7, a ground plate layer 1, and a signal wiring layer 9 are formed. And the respective terminals of the semiconductor chip 21 are connected to each other using bonding wires 22 made of Al or Cu.

In order to produce a resin-sealed package using the lead frame 20 according to the present invention, as shown in FIG. 3A, the lead frame 20 having the above-mentioned structure is used and placed on the ground plate layer 1 to wire. The plastic package 31 can be easily manufactured by sealing with the resin 30 together with the bonded semiconductor chip 21.

In order to manufacture a metal package, as shown in FIG. 3B, heat resistance for insulation is applied to the entire exposed surface of the ground plate layer 1 on the side of the lead frame 20 on which the semiconductor chip 21 is not mounted. An insulating epoxy resin layer 32 is applied, a heat-resistant insulating epoxy resin layer 33 for sealing is applied to a required position of the outer frame of the lead frame layer 4, and the semiconductor chip 21 is mounted on the ground plate layer 1. After mounting and wire bonding, a metal cap 34 capable of encapsulating the semiconductor chip 21 and the inner lead portion is placed on the heat-resistant insulating epoxy resin layer 33 for sealing and sealed, and a metal package 35 having excellent electromagnetic shielding property is obtained. Can be easily manufactured.

[0045]

The present invention, as a lead frame for a high-speed LSI, can have a large number of pins and a narrow lead tip pitch, and exhibits excellent heat dissipation, low noise characteristics, and manufacturability. As a result of various studies on the multi-layered lead frame structure aiming at a lead frame having a structure capable of remarkably improving the bonding characteristics, as a result, a rectangular frame shape in which a space between the leads is separated from each lead and connected to a power supply lead The structure in which the lead frame layer on which the power source layer is formed and the ground plate layer are bonded and laminated with a heat-resistant insulating epoxy resin layer can improve the heat dissipation, low noise characteristics, manufacturability, and wire bonding characteristics by increasing the number of pins. Further, an insulating material layer made of a heat-resistant insulating epoxy resin thin film or a ceramic thin film is interposed at a required portion on the substrate. The structure in which inner leads of Al thin film wiring or Cu thin film wiring Te, and finding that it is possible that narrow pitch of the lead tip pitch, and have completed the present invention.

[0046]

[Example] 0.35 m thick made of 42Ni-Fe alloy
The band-shaped low thermal expansion alloy plate of m is used as a metal plate for grounding, and a grounding plate layer (30 mm in length × 30 mm in width) of a required shape having a plurality of 0.2 mm × 3 mm protrusions in the peripheral portion is formed into 4 parts.
It was formed by etching so that it could be punched out individually. Further, after masking to expose the grounding surface of the grounding plate layer to the semiconductor chip, an Al thin film is vapor-deposited to a thickness of 5 μm to remove the masking, and the following heat-resistant insulating epoxy resin is applied to the required surface other than the grounding surface. The thin film was formed by screen printing to a thickness of 0.2 mm.

Heat-resistant insulating epoxy resin Main resin Resin: Novolac epoxy resin 45% Filler: Coupling-treated barium sulfate + silica 45% Pigment: Cyanine green 2% Solvent: Carbitol acetate 8% Curing agent Curing 2-methylimidazole 11 parts (Main agent 10
The main component was well dispersed and mixed before adding the curing agent. The obtained heat-resistant insulating epoxy resin had a pot life of 8 hours and a viscosity of 450 poise / ° C.

Thickness made of 42Ni-Fe alloy 0.15
Using a low thermal expansion alloy plate of mm as a lead frame substrate, a lead frame (vertical 40 mm x width 40 mm) having a rectangular frame-shaped power source layer separated from each lead and connected to a power lead in the space inside the lead tip is used. Four pieces were formed by etching so that they could be punched. Further, after masking to expose the rectangular frame-shaped power supply section and the surface to be wire-bonded, an Al thin film is vapor-deposited to a thickness of 5 μm to remove the masking. A heat-resistant insulating epoxy resin thin film similar to the above was provided to a thickness of 0.2 mm by screen printing.

After placing the lead frame substrate on the grounding metal plate and subjecting it to heat curing treatment under the condition of 150 ° C. × 60 minutes for integration, the lead frame layer is placed on the heat-resistant insulating epoxy resin thin film. A by masking and vapor deposition means
l Thin film wiring was formed to a thickness of 0.01 mm to provide an inner lead, and the lead projection of the ground plate layer and the lead frame were connected by spot welding. Next, a high-speed LSI chip was fixedly mounted on the central portion of the ground plate layer with an adhesive, and then the semiconductor chip, the Al thin film wiring, the rectangular frame-shaped power supply unit, and the ground plate were bonded with Al wires. The rate of bonding mistakes when performing the above wire bonding is 2/2000, and the rate of bonding mistakes is greatly reduced compared to the conventional multilayer lead frame rate of 50/2000 using a polyimide insulating double-sided adhesive film. However, productivity has improved dramatically.

Each of the lead frame portions on which the above chips were mounted and wire bonding was completed were resin-sealed, and then unnecessary frame portions were cut and separated to obtain four resin-sealed high-speed LSI packages. When the heat dissipation of the resin-encapsulated package was examined, it was suitable for power consumption of 2 W or more. Moreover, when the electrical characteristics were examined, there was no signal distortion and the response was extremely good. Compared with the conventional single layer lead frame, the power supply noise could be reduced to less than 1/2.

[0051]

The lead frame according to the present invention has the following various effects. 1) By having an Al or Cu thin film wiring layer, extremely fine wiring can be realized, the number of pins can be increased, and high speed LS can be achieved.
It can also be used for high integration semiconductor devices such as I. 2) By using a heat-resistant insulating resin containing a filler in the adhesive lamination of the ground plate layer and the lead frame layer, the bonding load and ultrasonic output of the wire bonder can be concentrated, so the wire bonding characteristics are outstanding. As a result, the bonding strength and bonding uniformity of the wires can be improved, and the reliability of wire bonding can be improved, and the productivity can be significantly improved. 3) By using heat resistant insulating resin or Al ₂ O ₃ for the insulating material layer, it can be applied to metal packages, ceramics packages, etc. Especially when heat resistant insulating resin is used, it is composed of fine Al or Cu thin film wiring. Since it is not attacked by water such as developer or stripping solution used in the process of forming the signal wiring layer, highly precise fine wiring can be performed, and the thickness can be reduced when dense Al ₂ O ₃ is used. Therefore, the semiconductor device and the package can be thinned. 4) Although the wiring has been miniaturized by making the area of the rectangular frame-shaped power supply unit large by using a multilayer structure,
Power supply noise, signal distortion, etc. are kept low, responsiveness is extremely good, and high speed is also supported. 5) By increasing the area of the ground plate with a multilayer structure, the heat dissipation is improved to 2 W or more, and a high-speed MPU with power consumption of 2 to 3 W can also be mounted. 6) Since the lead frame substrate is provided with the rectangular frame-shaped power supply unit, the process of manufacturing the parts is simplified, and since it can be bonded to any position of the rectangular frame-shaped power supply unit, the bonding from the semiconductor element is easy. In addition, the resistance of the bonding wire can be reduced by shortening the bonding wire, and power supply noise, signal distortion, etc. can be reduced. 7) By mainly packaging the lead frame having the above effects, it is possible to provide a resin-sealed type and a metal cap-sealed type semiconductor package with good productivity and at low cost.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a laminated state of an embodiment of a lead frame according to the present invention.

2A to 2D are longitudinal explanatory views showing a manufacturing process of a lead frame according to the present invention.

FIG. 3A is a resin-sealed semiconductor package according to the present invention, and b is a metal cap-sealed semiconductor package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground plate layer 2 Protrusion 3 Heat-resistant insulating epoxy resin layer 4 Lead frame layer 5 Lead 6 Power supply lead 7 Square frame power supply layer 8 Insulating material layer 9 Signal wiring layer 10, 11 Thin film 20 Lead frame 21 Semiconductor chip 22 Bonding wire 30 Resin 31 Plastic package 32 Heat-resistant insulating epoxy resin layer for insulation 33 Heat-resistant insulating epoxy resin layer for sealing 34 Metal cap 35 Metal package

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 63/00 NLD 8830-4J

Claims (8)

[Claims] 1. A ground plate layer having a plurality of lead projections on its periphery, and a lead formed with a rectangular frame-shaped power supply layer separated from each lead and connected to a power supply lead in a space inside the lead tip. The frame layer is adhesively laminated with a heat-resistant insulating resin layer that covers a part of the lead and the rectangular frame-shaped power supply layer, and the protrusion of the ground plate layer and the ground lead of the lead frame layer are connected to each other. A signal wiring layer made of Al thin film wiring or Cu thin film wiring with an insulating material layer made of a heat-resistant insulating resin thin film or a ceramic thin film interposed in a required portion on the lead frame layer excluding the central portion of the rectangular frame-shaped power supply portion layer. A lead frame characterized in that an inner lead is formed by forming the. 2. A grounding metal plate formed so that a grounding plate layer having a required shape and having a plurality of protrusions on its peripheral portion can be punched out,
At least the step of forming a wire bonding thin film on the surface to be grounded with the semiconductor chip and further providing a heat-resistant insulating resin thin film on the required surface other than the surface to be grounded, and separating the leads from the leads in the space inside the tip of the leads. And a lead frame metal plate that has a rectangular frame-shaped power supply layer connected to the power supply lead and is capable of being punched, and forms a wire bonding thin film on the rectangular frame-shaped power supply part and the wire bonding planned surface. Furthermore, the step of providing a heat-resistant insulating resin thin film or ceramics thin film on the required part of the rectangular frame-shaped power supply layer excluding the central part, and the heat-resistant insulation between the two by placing the lead frame metal plate on the ground metal plate. After bonding and integrating with a resin layer, an Al thin film wiring or a Cu thin film wiring is formed on the heat resistant insulating resin thin film or the ceramic thin film, and The provided Rido, and manufacturing method of lead frame, characterized in that comprising the step of connecting the leads of the lead protrusion and the lead frame forming metal plate of the ground plate. 3. A heat-resistant insulating resin thin film is provided on a required surface by using a grounding metal plate in which the thin film for wire bonding is clad in advance instead of the step of forming a thin film for wire bonding on at least a surface to be grounded with a semiconductor chip. The method of manufacturing a lead frame according to claim 2, characterized by the steps. 4. A ground plate layer having a plurality of lead projections on its periphery, and a lead formed with a rectangular frame-shaped power supply layer separated from each lead and connected to a power supply lead in a space inside the lead tip. The frame layer is adhesively laminated with a heat-resistant insulating resin layer that covers a part of the lead and the rectangular frame-shaped power supply layer, and the protrusion of the ground plate layer and the ground lead of the lead frame layer are connected to each other. A signal wiring layer made of Al thin film wiring or Cu thin film wiring with an insulating material layer made of a heat-resistant insulating resin thin film or a ceramic thin film interposed in a required portion on the lead frame layer excluding the central portion of the rectangular frame-shaped power supply portion layer. A semiconductor package, which is mainly composed of a lead frame having an inner lead formed therein and is sealed with a resin together with a semiconductor chip fixed to a ground plate layer. 5. A ground plate layer having a plurality of lead projections on its peripheral portion, and a lead formed with a rectangular frame-shaped power supply layer separated from each lead and connected to a power supply lead in a space inside the lead tip. The frame layer is adhesively laminated with a heat-resistant insulating resin layer that covers a part of the lead and the rectangular frame-shaped power supply layer, and the protrusion of the ground plate layer and the ground lead of the lead frame layer are connected to each other. A signal wiring layer made of Al thin film wiring or Cu thin film wiring is formed on the lead frame layer by interposing an insulating material made of a heat-resistant insulating resin thin film or a ceramic thin film at a required portion except for the central portion of the rectangular frame-shaped power supply layer. Mainly composed of the lead frame that formed the inner lead, the exposed surface of the ground plate was sealed with a heat-resistant insulating resin, and the metal chip encapsulating the semiconductor chip and the inner lead fixed to the ground plate. A semiconductor package in which the cap is sealed with a heat-resistant insulating resin. 6. A filler 40 in which the heat-resistant insulating epoxy resin is a mixture of 40% to 50% of a novolac epoxy resin and barium sulfate and silica which have been previously subjected to a coupling treatment.
% To 50%, 1% to 2% of pigment, and 8% to 9% of solvent carbitol acetate as a main component as 100 parts, and 6 to 20 parts of an imidazole-based curing agent are prepared. The lead frame according to claim 1. 7. A filler 40 in which the heat-resistant insulating epoxy resin is a mixture of 40% to 50% of a novolac epoxy resin and barium sulfate and silica which have been previously subjected to a coupling treatment.
% To 50%, 1% to 2% of pigment, and 8% to 9% of solvent carbitol acetate as a main component as 100 parts, and 6 to 20 parts of an imidazole-based curing agent are prepared. The method for manufacturing a lead frame according to claim 2 or 3. 8. A filler 40 in which the heat-resistant insulating epoxy resin is a mixture of novolac epoxy resin 40% to 50% and barium sulfate and silica which have been previously subjected to a coupling treatment.
% To 50%, 1% to 2% of pigment, and 8% to 9% of solvent carbitol acetate as a main component as 100 parts, and 6 to 20 parts of an imidazole-based curing agent are prepared. The semiconductor package according to claim 4 or claim 5.