JPH0697318A - Wiring board for semiconductor device - Google Patents

Abstract

PURPOSE:To maintain high rigidity of the micro work of an internal wiring, an external wiring and the external terminals formed in one body with the external wiring by electrically interconnecting the internal wiring and the external wiring with the electrically connecting holes provided in an insulating base board. CONSTITUTION:The electrically conductive connection between an internal wiring and an external wiring is formed with electrically connecting holes 16 formed in an insulating board. Further, an external terminal 15 is so formed as to stride over an annular insulator 17 used for external terminal support to project outwardly. Thereby, the internal wiring is constituted of thin metal which excels in electrical conductivity, and the external wiring is constituted of a metal plate of large rigidity, so that the flatness of the external wiring of a semiconductor device may be maintained, though the semiconductor device has a very fine internal wiring, and the semiconductor device may be handled by the same method as before.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board for semiconductor devices, and more particularly to a wiring board suitable for manufacturing semiconductor devices such as ASICs and microprocessors having multiple terminals.

[0002]

2. Description of the Related Art Conventionally, MPU (Micro Process)
sor unit), ASIC (Applicati)
on Specific Integrated Ci
As a method of manufacturing a multi-terminal semiconductor device such as rcuits) at a low cost, a plastic QFP (Quad Flat Pa) sealed with an epoxy resin using a lead frame having external leads extending in four directions.
package) or plastic QFJ (Quad)
Flat J-Lead Package) and the like are often used. As shown in FIG. 7, the lead frame used for such conventional QFPs and QFJs, which plays a role of signal transmission, power supply, etc., is close to 42 alloy (42% nickel-containing iron-based alloy) or 42 alloy. A thin plate of copper alloy or the like having electrical conductivity and rigidity is manufactured by a photo-etching method or the like, and a die pad portion 61 for mounting a semiconductor element and an inner lead portion 62 for performing bonding connection with the semiconductor element. , The outer lead portion 63 for connecting the semiconductor element to an external circuit, and the like.

In recent years, with the progress of lithography technology in the formation of semiconductor elements, the degree of integration of semiconductor elements has increased, and the number of high-performance semiconductor elements represented by MPU, ASIC, etc. has been increasing. In such a situation, it is necessary to make the pitch of the inner leads of the lead frame small, but in the processing of the metal thin plate by the photo etching method, the processing limit of the pitch depends on the plate thickness,
For example, in the case of a metal plate having a plate thickness of 0.150 mm,
The 220 mm pitch is the minimum pitch that can secure a flat width capable of forming a bonding connection with the external electrode on the semiconductor element. Therefore, in order to cope with the increase in the number of terminals of semiconductor elements, it is unavoidable to take measures to reduce the thickness of the metal plate.

When the thickness of the metal plate is reduced in order to reduce the pitch of the inner leads, the fine lead portions are bent during handling, and the flatness of the outer leads used for connection with an external circuit is maintained. Causes problems such as difficulty. At present, even in the case of 42 alloy, which has a high rigidity, that is, a deformation is small even when a displacement is applied, the plate thickness is 0.
About 10 mm is the allowable limit for thinning, 0.190-
The limit of the inner lead is about 0.200 mm pitch. For such problems, plastic QF
In order to further reduce the pitch of the inner leads of P and QFJ, there has been proposed a lead frame in which the inner leads and the outer leads are formed by separate members.

One of them is a wiring pattern 71 provided on a printed circuit board by sandwiching a lead frame by a glass triazine-based printed wiring board as shown in FIG. 8 (A).
To the external electrode of the semiconductor element mounted on the die pad 72, and the wiring pattern is electrically connected through the through hole 73, and QFP (Quad Flat Package)
The outer lead 74 protruding as described above is formed. According to this method, the inner leads can be formed by etching a copper foil with a thickness of 35 μm laminated on a printed wiring board, which has the advantage that the pitch of the leads can be narrowed, but on the other hand, it can be formed beforehand. In addition to requiring accurate alignment of the lead frame with the through-hole formation part of the printed wiring board, the manufacturing process of the lead frame is required in addition to the conventional multilayer printed wiring board manufacturing process. In addition to being complicated, there is a problem that the cost is increased.

As another example, as shown in FIG. 8B, the inner lead portion is provided with TAB (Tape Automated).
Bonding), and a technique is proposed in which a lead frame 75 having no die pad and a TAB lead 76 are directly connected to cope with the multi-terminal of a semiconductor element. However, similar to the above-mentioned printed wiring board sandwiching the lead frame,
In the structure of the lead frame by this method, the manufacturing process of the TAB and the manufacturing process of the lead frame are independent of each other, and further, it is necessary to connect the leads to each other in a fine region, so that the manufacturing yield is improved. However, there is a problem that it is difficult to reduce the manufacturing cost.

[0007]

As described above, in the conventional lead frame formed by photoetching a metal plate, the inner leads are made narrower in pitch while maintaining the flatness of the outer leads. Is at the limit. Further, in the method of forming the inner lead region by the printed circuit board or the TAB, the manufacturing process of another member is involved, so that the process is complicated, and the wiring part of the lead frame and Since a circuit part formed on a printed circuit board or a connection process in a fine area with a TAB lead is required, there is a problem that it is difficult to improve the manufacturing yield, and it reaches a practical stage. Not in.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a wiring board for a semiconductor, which is composed of a double-sided metal laminated substrate in which conductive metals are laminated on both sides of an insulating substrate. Internal wiring for connection with the bonding wire from the connection terminal is formed, and external wiring for connection with the external circuit is formed on the other surface, and the external wiring is an external circuit extending from the insulating substrate. Is a wiring board for a semiconductor device, which is formed integrally with a connection terminal for connection with the internal wiring and the external wiring is conductively connected by an electrical connection hole provided in the insulating substrate.

Further, the internal wiring is made of a metal having a small thickness, and the external wiring is made of a metal having a thickness or rigidity larger than that of the internal wiring. Preferably, the internal wiring is laminated on an insulating substrate. The external wiring is formed by etching the copper foil, and the external wiring etches the copper foil, the copper alloy, the 42 alloy, etc., which have a greater thickness and rigidity than the internal wiring laminated on the insulating substrate, and also etch the insulating substrate. Thus, the end portion of the external wiring is projected from the end portion of the insulating substrate to serve as a terminal for connection with an external circuit. Further, the insulating substrate is preferably a flexible insulating substrate made of a die pad portion or a polyimide resin supporting the die pad portion.

[0010]

By assembling a semiconductor element using the wiring board for a semiconductor device of the present invention, it is possible to easily cope with connection with a semiconductor element having a large number of external electrodes. Further, since the internal wiring can be made of a thin metal having excellent electric conductivity and the external wiring can be made of a metal plate having high rigidity, the flatness of the external wiring of the semiconductor device can be achieved even though it has fine internal wiring. Can be maintained, and the semiconductor device can be handled in the same manner as the conventional method. Further, the wiring board of the present invention can be constructed without dividing the manufacturing process, as compared with the conventional one in which separate members such as a printed wiring board and a lead frame or a TAB and a lead frame are integrated, so that the manufacturing process is simplified. . Further, when a semiconductor device is manufactured, it is possible to form a larger metal die pad for mounting a semiconductor element with an arbitrary metal plate as compared with a lead frame forming a conventional plastic QFP or QFJ. A semiconductor device capable of effective heat dissipation can be provided.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a wiring board for a semiconductor device according to an embodiment of the present invention. FIG. 1 (a) is a plan view and FIG. 1 (b) is shown respectively. The internal wiring 11 for conductive connection with the semiconductor element is formed of a metal foil laminated on the surface of the insulating substrate 12, for example, a metal foil having a high electric conductivity such as a copper foil. For the insulating substrate, polyimide, glass polyimide, polytetrafluoroethylene, or the like, which has a low dielectric constant and dielectric loss, is used. One end of the internal wiring is conductively connected to the connection terminal of the semiconductor element mounted on the die pad 13 by wire bonding such as a gold wire. On the surface opposite to the surface where the internal wiring of the insulating substrate is formed,
The external wiring 14 is laminated, and the external wiring is integrally formed with an external terminal 15 for connecting an external circuit, which extends around the insulating substrate.

External wiring and external terminals are Kovar, 4
It is composed of a metal plate or metal foil having high rigidity such as an iron-based alloy such as 2 alloys or a copper-based alloy. Further, the internal wiring and the external wiring are electrically connected holes 16 formed on the insulating substrate.
To form a conductive connection. In addition, external terminal 1
Reference numeral 5 is formed so as to project outward in a manner straddling a ring-shaped insulator 17 for supporting external terminals. For the ring-shaped insulator, various materials can be used, including the same material as the insulating substrate forming the internal circuit and the external circuit.

FIG. 2 is a rear view of the semiconductor device wiring board shown in FIG. When the semiconductor element mounting die pad 13 is provided on the side opposite to the internal wiring of the insulating substrate 12 and the semiconductor element is mounted in the opening provided on the internal wiring forming surface, the inside of the electrical connection hole 16 is Since it is possible to use a die pad having a size of the region, effective heat dissipation can be achieved by using a metal or the like having excellent thermal conductivity as the die pad. Further, more effective heat dissipation can be achieved by directly attaching the semiconductor element to the metal die pad using an adhesive having a high thermal conductivity or the like.

FIG. 3 is a sectional view showing an embodiment of a semiconductor device manufactured by using the wiring board for a semiconductor device of the present invention. The external electrode 19 on the semiconductor element 18 and the end of the internal wiring 11 are connected by a thin metal wire 20 such as a gold wire or an aluminum wire. The external terminal 15 is bent in a gull wing shape, and the external terminal is 42 A material such as an alloy that does not cause metal fatigue even if it is formed into a J-shape or a gull-wing shape is used.

FIG. 4 shows another embodiment of the semiconductor device. The semiconductor device is manufactured by the TAB assembly method in which the tip end portion of the internal wiring 11 is projected from the insulating substrate 12 to form the finger lead 21, and the finger lead 21 and the protruding electrode 22 formed on the external electrode on the semiconductor element are directly bonded. It shows the case of assembling.

1 to 4 described above, the external terminal is supported by the ring-shaped insulator for supporting the external terminal, and the ring-shaped insulator is used as a dam bar for molding. In the assembly, whether or not the dam bar is left may be left, and whether or not the ring-shaped insulator is formed may be left or right. Further, since a material having excellent insulating properties is used as the ring-shaped insulator of the present invention, not only does it not need to be cut after the semiconductor device is assembled, but also the flatness of the external terminals of the semiconductor device can be more surely ensured. Is possible.

Further, the wiring board for a semiconductor device of the present invention has been described as an MPU, an ASIC, etc. for a single chip package as shown in FIGS. 1 to 4, but, for example, an MCM (Multi Ch) having a plurality of semiconductor elements.
It can also be used as a wiring board for a semiconductor device for manufacturing an ip module). When used in such a semiconductor device, reliability is improved by using an insulating substrate such as glass polyimide, polytetrafluoroethylene, polyphenylene oxide, etc., which has a low dielectric constant in the high frequency region and a low dielectric loss. A high-speed and high-speed operation semiconductor device can be provided.

Next, referring to FIG. 5, an example of a method for manufacturing a wiring board for a semiconductor device of the present invention will be described. An example of manufacturing a wiring board for a semiconductor device using a polyimide substrate as an insulating substrate will be described. 500m in size as metal for external wiring
m × 500 mm, thickness 0.1 mm 42 alloy, N
-Methyl-2-pyrrolidone A polyamic acid varnish obtained by dissolving 30% by weight of a polyamic acid solid compound synthesized from pyromellitic acid anhydride in a solvent is applied onto a 42 alloy plate 31 by a screen printing method, and a thickness after drying. A polyamic acid coating film 32 having a thickness of 10 μm was formed. On the other hand, as internal wiring metal, size 500 mm x 500 mm, thickness 0.018 m
On one side of the rolled copper foil 33 having a thickness of 10 m, a polyamic acid varnish was dried by a screen printing method in the same manner as the 42 alloy to have a thickness of 10 μm.
A polyamic acid coating film 34 of m was obtained (FIG. 5 (a)).

Next, with both metal surfaces obtained in FIG. 5 (a) outside, a polyimide film 35 of 50 μm is provided between them, and pressure is applied under the conditions of 15 to 30 kgf / cm ² , 260 ° C. and 120 seconds. The temperature was raised to accelerate the polymerization reaction of polyamic acid to obtain polyimide, and a polyimide substrate having a metal laminated on both sides was obtained (FIG. 5 (b)).

The obtained double-sided metal laminated polyimide substrate is
0.1m when sandwiched by 0.5mm thick aluminum plates
Set it on the processing stage of a drilling machine (manufactured by OILES Co., Ltd.) equipped with an m-diameter drill 36 (manufactured by Toshiba Tungaloy) and use it as an internal lead under the processing conditions of spindle rotation speed 80,000 rpm and drill feed speed 6.2 m / min. A hole 37 is provided at a place where connection with an external lead should be made (see FIG. 5).
(C)).

Then, the perforated double-sided metal polyimide substrate is treated with a palladium chloride solution, then electroless copper plated, and further 3 A / d in a copper sulfate bath at 30 ° C.
A current density of m ² was applied for 10 minutes to form a through hole 38 of metallic copper having a thickness of 15 μm (FIG. 5D). Next, a negative dry film resist 39 (Laminar AG manufactured by Morton International) is laminated on both sides to form a pattern for forming a semiconductor element mounting die pad portion 40, an external wiring forming window portion 41, a window portion 42 and the like. Formed. (FIG.5 (e)).

After forming a predetermined pattern on the metal portion of the double-sided metal-laminated polyimide substrate on which a resist pattern has been formed using an etching solution composed of ferric chloride, the dry film resist is peeled off using an alkali peeling solution ( FIG. 5 (f)).

Next, the polyimide 43 exposed from the metal removing part was dissolved and removed in an 80% by volume ethanol solution adjusted to 1N potassium hydroxide (FIG. 5 (g)). Further, a cation-type electrodeposition resist 44 was electrophoretically coated on the entire metal portion to form a resist pattern of a portion necessary for forming internal wiring, external wiring, through hole lands, etc. (FIG. 5 (h)). ).

Further, the metal portion exposed from the resist is etched to form the internal wiring 45, the external wiring 46, the semiconductor element mounting die pad 47, etc. in the same manner as in the method shown in FIG. 5F, and then, The resist was removed using an alkaline stripping solution consisting of a 10% sodium hydroxide solution (FIG. 5 (i)). The circuit board (i) thus manufactured is electroless nickel plated to a thickness of 3 μm, and then electro-gold plated to a thickness of 3 μm to perform a metal surface treatment. Was completed.

Further, in the wiring board for semiconductor device of the present invention, polyimide, polyamide, glass polyimide, PEEK, PET or polytetra which serves as an insulating substrate is prepared by using an epoxy adhesive or an acrylic adhesive for the metal on both sides. It may be formed by bonding it to an insulator having heat resistance and insulation such as fluoroethylene, or an adhesive on the polyimide side of a non-adhesive type single-sided polyimide substrate (for example, ESPANEX: Nippon Steel Chemical). Alternatively, the second metal foil or the metal plate may be bonded together by using.
After bonding a metal foil with excellent electrical conductivity such as copper foil to be the internal wiring with a polyimide resin using an adhesive, or in the state of a single-sided copper foil polyimide substrate, remove the metal and polyimide resin to be the external wiring formation part. The wiring board of the present invention can be constructed by removing the punching and adhering the second metal foil or the metal plate, which will be the surface on which the external leads are formed, with an adhesive.

FIG. 6 shows a method of manufacturing by removing the polyimide resin by punching. A copper foil 51 is laminated on an insulating substrate 52 with an adhesive 53, and an adhesive layer for laminating metal is formed on the other surface of the insulating substrate (see FIG. 6).
(A)), the mold 54, the window 55, the conductive connection hole 5
6. Form the external wiring forming window 57 (see FIG. 6).
(B)). The 42 alloy plate 58 is laminated on the adhesive layer (see FIG. 6).
(C)) A resist 59 is applied while leaving the conductive connection holes, and electroconductive plating is used to form the front and back conductive connections (FIG. 6D).

Next, the resist 59 is removed, and in the subsequent operations, resists for forming an etching pattern are applied on the front and back surfaces in the same manner as in FIG. 5 (i), and internal wiring and external wiring are formed by etching, and a wiring board. To form. The insulating substrate can be removed by a method using an excimer laser or the like instead of the method using a mold.

Further, when the semiconductor element consumes a large amount of power, the metal die pad portion, which is the semiconductor element mounting portion, is made of a metal having a high thermal conductivity, which is different from the metal for external wiring. The present semiconductor device circuit board may be completed by, for example, bonding the semiconductor device circuit board after or during part of the manufacturing process. Further, the manufacturing method of the wiring portion in the circuit board of the present invention is not limited to the method of removing an unnecessary portion like the etching shown in the present embodiment, electroless plating, by a film forming means such as a sputtering ring, A wiring portion may be formed, or a wiring portion having a predetermined thickness may be further formed on the wiring portion formed by such a film forming means by a method such as electroplating.

[0029]

According to the wiring board for a semiconductor device of the present invention, the metal for internal wiring, which needs to be formed with a fine pitch, and the metal for external wiring, which is required to have mechanical strength, are provided on both surfaces of the insulating substrate. , The wiring part was formed by forming and etching each, and the internal wiring and the external wiring were conductively connected by the electrical connection hole. Therefore, the internal wiring is finely processed and the rigidity of the external terminal integrated with the external wiring and the external wiring. Can be kept high. As a result, even though the wiring board has extremely fine internal wiring, it is easy to handle after assembling the semiconductor device, and is particularly sufficient to maintain the coplanarity of the terminals after molding the external terminal portion into a gull wing shape. Since it is possible to provide a semiconductor device having various strengths, it is possible to maintain reliability in soldering the external terminal and the circuit board. TCP suitable for fine pitch
(Tape Carrier Package) and the advantage of the lead frame having the high hardness of the external leads are combined, and thus the wiring board having the advantage can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a plan view and a sectional view of a semiconductor device circuit board according to an embodiment of the present invention.

2 is a rear view of the circuit board for a semiconductor device of the embodiment of FIG.

FIG. 3 is a cross-sectional view of a semiconductor device using the semiconductor wiring board of the present invention.

FIG. 4 shows a front view showing another embodiment of a semiconductor device circuit board and a cross-sectional view of a semiconductor device using the same.

FIG. 5 is a diagram showing an example of a method for manufacturing a circuit board for a semiconductor device of the present invention.

FIG. 6 is a diagram showing another example of the method for manufacturing a circuit board for a semiconductor device of the present invention.

FIG. 7 is a plan view of a conventional lead frame.

FIG. 8 shows a combination of a conventional printed circuit board for plastic QFP and QFJ and a lead frame.

[Explanation of symbols]

11 ... Internal wiring, 12 ... Insulating substrate, 13 ... Die pad, 14 ... External wiring, 15 ... External terminal, 16 ... Conductive connection hole, 17 ... Ring insulator, 18 ... Semiconductor element, 19 ...
External electrode, 20 ... fine metal wire, 21 ... finger lead,
22 ... Projection electrode, 31 ... 42 Alloy plate, 32 ... Polyamic acid coating film, 33 ... Rolled copper foil, 34 ... Polyamic acid coating film, 35 ... Polyimide film, 36 ... Drill, 37 ...
Holes, 38 ... Through holes, 39 ... Negative dry film resist, 40 ... Semiconductor element mounting die pad section, 41
... window portion for forming external wiring, 42 ... window portion, 43 ... polyimide, 44 ... cationic type electrodeposition resist, 45 ... internal wiring,
46 ... External wiring, 47 ... Die pad for mounting semiconductor element,
51 ... Copper foil, 52 ... Insulating substrate, 53 ... Adhesive, 54 ...
Mold, 55 ... Window portion, 56 ... Conductive connection hole portion, 57 ... External wiring forming window portion, 58 ... 42 Alloy plate, 59 ... Resist

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H05K 3/46 Q 6921-4E // C23F 1/02 8414-4K

Claims (3)

[Claims] 1. A wiring board for a semiconductor device comprising a double-sided metal laminated board in which a conductive metal is laminated on both sides of an insulating board, wherein the mounting portion of the semiconductor element and the internal wiring for connection with the semiconductor element are insulated. It is provided on one side of the board, and the other side has external wiring for connecting to an external circuit and external terminals for connecting to an external circuit integrated with the external wiring, and insulates the internal wiring from the external wiring. A wiring board for a semiconductor device, characterized in that a conductive connection is formed through an electrical connection hole provided in the flexible substrate. 2. The metal for internal wiring and the metal for external circuit are metals having different thicknesses or materials, and the metal for external circuit is thicker or has higher rigidity than the metal for internal wiring. The wiring board for a semiconductor device according to claim 1, wherein the wiring board is a metal. 3. The insulating substrate is a polyimide resin, the metal for the internal wiring is copper or a copper alloy, and the metal for the external wiring is a copper alloy or a nickel-iron alloy. The wiring board for a semiconductor device according to any one of 1.