JPH04199668A - Lead frame, semiconductor device provided therewith, and method of assembling the device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a lead frame for mounting a semiconductor element, and particularly to a lead frame that can meet the requirements for multi-bin miniaturization and high heat dissipation when packaged, and a semiconductor using this lead frame. The present invention relates to a device and a method for assembling the semiconductor device.

[Conventional technology]

Chikami ASIC (Application 5 peci) represented by gate arrays, standard cells, etc.
The gate density of fic integrated circuit (C1rcuit) chips continues to increase as the microfabrication technology of LSI increases. Along with this, lead frames used for ASIC chips also tend to have more pins, and lead frames with more than 200 pins are now in practical use. As one of the countermeasures for increasing the number of bins in lead frames, a fine pattern of inner leads is formed by etching the metal foil pasted on the insulating film. A technique for assembling a composite lead frame by joining a lead frame having only inner leads and outer leads, for example, is disclosed in Japanese Patent Laid-Open No. 62-2329.
No. 48 is disclosed in Japanese Unexamined Patent Publication No. 2-22850. On the other hand, because it is easier to increase the degree of integration in ASIC chips, there is a tendency to shift from the conventional bipolar ECL technology to CMO3 technology to achieve even higher integration. As chips become more highly integrated, clock frequencies tend to increase. In this case, in an ECL gate array, the power consumption hardly changes even if the clock frequency increases, whereas in a CMOS gate array, the power consumption increases significantly as the clock frequency increases.

[Problem to be solved by the invention]

By the way, in order to meet the increasing demand for high integration and multi-bin semiconductor chips in the future, it is conceivable to form a CMOS gate array using the above-mentioned composite lead frame. In that case, since the CMOS gate array has a high clock frequency and consumes a large amount of power, the chip generates a large amount of heat, and therefore it is necessary to take measures for heat dissipation. However, in the above-mentioned composite lead frame, the inner lead formed in a superfine pattern and the lead frame having only the outer lead are simply joined, so it does not have sufficient heat dissipation characteristics. Not yet. Therefore, in order to form a semiconductor device such as a CMOS gate array with a high clock frequency, it is necessary to transfer mold the sealing resin with the heat dissipation fin made of metal such as A1 thermally connected to the back surface of the chip. However, performing resin sealing with the radiation fins thermally connected to the back surface of the chip in this way not only increases the number of work steps in the assembly process and is time-consuming, but also requires the use of TAB tape (Tape Automated Bo
Abbreviation for ndiog: Inner leads with a fine pattern of metal foil are formed on an insulating film.While maintaining connectivity between the leads of the tape and the leads of the lead frame (L/F), the heat dissipation fins can be attached to the semiconductor chip. There is a problem in that it is difficult to connect to the back side, resulting in increased manufacturing costs. The present invention has been made in view of these problems, and its purpose is to provide a lead frame that allows for an even larger number of pins and has excellent heat dissipation characteristics. An object of the present invention is to provide a semiconductor device using the present invention. Another object of the present invention is to provide a method for assembling a semiconductor device that can reduce the number of work steps in the assembly process and reduce costs.

[Means to solve the problem]

In order to solve the above-mentioned problems, the lead frame of the present invention includes a TAB tape in which an inner lead having a finger portion that enables further bonding with a semiconductor element is formed in a predetermined pattern on an insulating film; It is characterized by comprising a lead frame member made of a metal material having a die pad that mounts and supports the TAB tape and an outer lead that is bonded to the inner lead, and a heat dissipation base material that is bonded to at least the die pad. Further, the semiconductor device of the present invention includes a semiconductor element mounted on a lead frame, an electrode of the semiconductor element being joined to a finger portion of the inner lead, and the inner lead and the outer lead being joined. , a semiconductor device packaged by resin sealing, wherein the semiconductor element passes through a hole formed in the die pad and is bonded to the heat dissipation base material, or the semiconductor element is bonded to the die pad. It is characterized by being mounted and supported. Further, in the method for assembling a semiconductor device of the present invention, the electrodes of the semiconductor element are bonded to the finger portions of the inner leads to form a device film, and the heat dissipation base material is placed opposite to the TAB tape mounting support surface of the die pad. The insulating film of the device film is bonded to the die pad of the lead frame with a heat dissipation base material, and the inner leads are bonded to the outer leads, and then resin-sealed. It is characterized by pancaging.

[Effect]

According to the lead frame and semiconductor device according to the present invention, since the TAB tape and the heat dissipation base material are used, it is not only possible to increase the number of pins into multiple bins, but also
Heat dissipation characteristics become good. Further, according to the method for assembling a semiconductor device according to the present invention, since the heat dissipation base material is simply bonded to the die pad in advance, the number of work steps in the assembly process does not increase and labor is not required, and the manufacturing cost is reduced. will hardly rise.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing one embodiment of a lead frame of the present invention, FIG. 2 is a perspective view of a semiconductor device member in which a semiconductor element is mounted on the lead frame of this embodiment, and FIG. 3 is a diagram showing ■-■ in FIG. It is a sectional view along a line. As shown in FIG. 1, the lead frame 1 in this embodiment mainly includes a lead frame member A, a TAB tape B
The device lead frame member A is made up of a metal alloy hoop material such as 42 alloy or copper alloy, and is formed into a predetermined pattern by photolithography. A die pad 3 having a rectangular hole 3a is provided. The tips of the outer leads 2 are plated with nickel to a thickness of 5 μm, followed by gold plating to a thickness of 2 μm. The TAB tape B is a film carrier for bonding, and is made of a material made by laminating a metal foil 5 such as copper foil on an insulating film 4 such as a polyimide resin film, and the metal foil 5 is photoresinated. It is provided with a predetermined number of inner leads 6 formed into a predetermined pattern by an etching method. The insulating film 4 has the same size and shape as the die pad 3. therefore,
A rectangular hole 4a is also formed in the center of the insulating film 4, through which the semiconductor element is disposed. Each inner lead 6 is provided in an overhanging manner, with the inner finger portion 6a protruding from the inner circumferential edge of the insulating film 4 and the outer finger portion 6b protruding from the outer circumferential edge of the insulating film 4. . Further, the heat dissipation block C is a rectangular block made of a ceramic-based material with high heat dissipation properties made of an inorganic compound such as aluminum nitride or aluminum oxide. As shown in FIGS. 2 and 3, the semiconductor device member S in which the semiconductor element 7 is mounted on the lead frame 1 of this embodiment passes through the hole 4a of the insulating film 4 of the TAB tape B and the hole 3a of the die pad 3. A semiconductor element 7 is disposed, and each electrode 7a of the semiconductor element 7 is joined to an inner finger portion 6a of the inner lead 6. Also,
An insulating film 4 is bonded onto the die pad 3 of the lead frame member A, and the outer finger portion 6b of each inner lead 6 is bonded to the inner end of the corresponding outer lead 2. Further, a heat radiation block C is bonded to the lower surface of the die pad 3 and the lower surface of the semiconductor element 7. In that case, since the thickness of the semiconductor element 7 is generally set larger than the thickness of the insulating film 4, a difference occurs in the thickness direction when assembling the semiconductor device member S.
This difference in the thickness direction is adapted to be absorbed by the die pad 3 of the lead frame member B. Therefore, the upper surfaces of the outer lead 2, the insulating film 4, and the electrode 7a of the semiconductor element 7 are substantially flush with each other, and the inner lead 6 is joined without being bent or bent. Similarly, the lower surfaces of the die pad 3 and the semiconductor element 7 are also substantially flush with each other, and the heat dissipation block C is stably and reliably joined. Next, a method for assembling the semiconductor device member S configured in this manner will be described. FIG. 4 is a diagram illustrating a method for assembling the semiconductor device member S. As shown in FIG. 4(a), first, an insulating film 4 made of polyimide resin with a thickness of 75 μm (for example, Kabuton V, etc.) is coated with an epoxy adhesive with a thickness of 20 μm. A TAB film carrier material is prepared by laminating a 27 μm' copper foil 5. By etching the copper foil 5, which is a film carrier material for TAB, into a predetermined pattern by photolithography, a total of 300 leads, including inner leads 6 with a pitch of 130 μm and inner leads 6 with a pitch of 300 μm, are formed. Tape B is formed. Then, electroless tin plating with a thickness of 04 μm' to 0.6 μm is applied to the entire conductor portion of the inner lead 6. In addition, as shown in FIG.
A semiconductor element, an LSI chip 7 with straight bumps 7a formed to have a height of 30 μm and an area of 70 μm, is mounted on the substrate, and the LSI chip 7 is positioned at a predetermined position within the hole 4a of the insulating film 4. Next, as shown in FIG. 4(b), the inner finger portion 6a of the inner lead 6 protruding into the hole 4a and the LSI chip 7
Device bonding with the straight bump 7a,
Further bonding is performed by gigantic bonding using constant pulse heat 9. Next, as shown in FIG. 2C, the device film 11 is formed by cutting the support part 10 that supports the outer lead 2 of the film carrier after device bonding. In addition, after applying approximately 0.5 mm of epoxy silver paste, for example, to the top surface of the heat dissipation block C, the heat dissipation block C is applied to the back surface of the die pad 3 of the lead frame member A at a temperature of about 150°C, as shown in FIG. The lead frame 12 with a heat dissipation block is formed by joining through a hardening process. Next, the device film 11 formed in this way
and the lead frame 12 with a heat dissipation block, as shown in the same figure (e).
Thermocompression bonding is performed using a resistance heating type lead bonding tool 13 as shown in FIG. In that case, a metal eutectic is generated between the gold plating of the outer leads 2 of the lead frame member A and the tin plating of the inner leads 6 of the device film 11, and the outer leads 2 and inner leads 6 are reliably joined. Become so. Furthermore, the insulating film 4 and the die pad 3 are bonded together via an epoxy adhesive, and the LSI chip 7 is bonded via an epoxy silver paste. In this way, the semiconductor device member S as shown in FIG. 2 is assembled. In this semiconductor device member S, the LSI chip 7 is directly connected to the heat radiation block through the hole 3a of the die pad 3, and the heat radiation effect is extremely good. Additionally, since the die pad 3 also serves as a mounting stage for the insulating film 4, stress due to the weight of the LSI chip 7 applied to the joint between the inner lead 6 and the outer lead 2 is alleviated. Although not shown, the semiconductor device members S assembled in this manner are transfer-molded with a sealing resin in a conventional manner to form a packaging semiconductor device. FIG. 5 is a diagram similar to FIG. 2 showing another embodiment of the lead frame of the present invention. Note that the same components as described above are given the same reference numerals, and detailed explanation thereof will be omitted. As shown in FIG. 5, in this embodiment, an LSI chip 7 is mounted on a metal die pad 3. As shown in FIG. Further, a heat dissipation block C is bonded to the lower surface of the die pad 3. The mounting portion of the LSI chip 7 on the die pad 3 is formed as a recess by counterbore or the like, and this recess allows the LSI chip 7 to be mounted.
The difference in thickness between the I-chip 7 and the insulating film 4 is accommodated. In this embodiment, the heat generated from the LSI chip 7 is radiated by the die pad 3, so depending on the amount of heat radiated from the LSI chip 7, the heat radiation block C can be omitted. In this way, since the TAB tape B and the heat dissipation base material (heat dissipation block and/or die pad) are used in the semiconductor devices according to any of the embodiments described above, the number of bins can be increased even further. Not only is this possible, but the heat dissipation properties are also improved.

Effects of the Invention As is clear from the above description, according to the lead frame and semiconductor device of the present invention, it is possible to perform fine pitch connection with a semiconductor element using TAB tape, and also to perform transfer molding using resin. Therefore, it is possible to increase the number of bins. Furthermore, since a heat dissipation base material is used, good heat dissipation characteristics can be obtained. On the other hand, according to the method for assembling a semiconductor device according to the present invention, the heat dissipation base material is simply bonded to the die pad in advance, and there is no need to add a heat dissipation body such as a heat sink afterwards, so the number of work steps can be reduced. This makes it possible to assemble semiconductor devices even more easily and reduces manufacturing costs.

FIG. 1 is an exploded perspective view showing one embodiment of a lead frame of the present invention.

FIG. 2 is a perspective view of a semiconductor device member assembled using this embodiment.

[Figure 3] FIG. 3 is a sectional view taken along the line ■-■ in FIG. 2. FIG.

[Figure 4] 3 is a diagram illustrating assembly of the semiconductor device in FIG. 2. FIG.

[Figure 5] Ru.

[Explanation of symbols]

1 Inner lead 2 Outer lead 3 Die pad 3a hole 4 Insulating film 4a hole 5 Metal foil (copper foil) 6 Inner lead 6a Finger portion 7 Semiconductor element 78 Semiconductor element electrode 10 Support bar 11 Device film 12 Lead frame A with heat radiation block Lead frame member B TAB tape C Heat dissipation block S Semiconductor device member patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Kenji Aoki (and 7 others) Engraving of drawings (no changes in content) Figure 4 Figure 4 (d) Procedural amendment 1) December 4, 1990 2!! Ming name 3, relationship with the case of the person making the amendment Patent applicant address 1-1-4, Ichigaya Kaga-cho, Shinjuku-ku, Tokyo;
Agent 6, drawings subject to amendment (plan)

Claims (9)

[Claims] 1. A TAB tape in which inner leads having finger portions that enable bulk bonding with semiconductor elements are formed in a predetermined pattern on an insulating film, and a die pad and inner leads for mounting and supporting this TAB tape. 1. A lead frame comprising: a lead frame member made of a metal material having an outer lead joined to the die pad; and a heat dissipation base material joined to at least a die pad. 2. The lead frame according to claim 1, wherein the die pad has a hole through which a semiconductor element is disposed. 3. The die pad as claimed in claim 1, wherein a portion on which a semiconductor element is mounted and supported is a recessed portion.
Lead frame listed. 4. The lead frame according to claim 1, wherein the heat dissipation base material is made of an inorganic compound such as aluminum nitride or aluminum oxide. 5. The lead frame according to claim 1, wherein the heat dissipation base material is made of a metal material different from the metal material of the lead frame member. 6. A state in which a semiconductor element is mounted on the lead frame according to claim 2, an electrode of the semiconductor element is joined to a finger portion of the inner lead, and the inner lead and the outer lead are joined. and a semiconductor device packaged by resin sealing, wherein the semiconductor element is disposed to penetrate into the hole of the die pad, and the semiconductor element is bonded to the heat dissipation base material. A semiconductor device characterized by 7. A semiconductor element is mounted using the lead frame according to claim 3, and the electrode of the semiconductor element is bonded to the finger portion of the inner lead, and the inner lead and the outer lead are bonded. 1. A semiconductor device packaged by resin sealing in a state in which the semiconductor element is mounted and supported on a recessed portion of the die pad. 8. The method for assembling a semiconductor device according to claim 6, wherein the electrodes of the semiconductor element are bonded to the finger portions of the inner leads to form a device film, and the heat dissipation base material is bonded to the TAB of the die pad. A lead frame with a heat dissipation base material is formed by bonding to the surface opposite to the supporting surface on which the tape is mounted, and the insulating film of the device film is bonded to the die pad of the lead frame with a heat dissipation base material, and the inner leads are bonded to the outer leads. and then packaging it by resin sealing. 9. The method for assembling a semiconductor device according to claim 7, wherein the electrodes of the semiconductor element are bonded to the finger portions of the inner leads to form a device film, and the heat dissipation base material is attached to the die pad. The TAB tape is bonded to the surface opposite to the support surface on which it is mounted to form a lead frame with heat dissipation base material, and the insulating film of the device film is bonded to the die pad of the lead frame with heat dissipation base material, and the inner leads are made into outer leads. A method for assembling a semiconductor device, which comprises bonding and then packaging by resin sealing.