JPS5837940A - Lead frame for semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To eliminate the penetration of humidity, contaminated ions, etc. through a support, and the adhesion of noble metallic plating to mounting part and supporting part by a method wherein the mounting part is supported by combining with external loading leads by an insulator. CONSTITUTION:An insulator 6 that is adhered to a plastic envelope consists of a resin sheet or film leaf whose coefficient of thermal expansion and hygroscopic swelling are close to those of the envelope, and is adhered to mounting part 1 and external loading leads 4a-4n, as well as covering them. As a result, a microgap does not exist between plastics, the envelope, that grows along a support part, and metal comprising the support part, thus this extremely lessens the penetration of a harmful object. In addition, the mounting part is isolated electrically from the part with electric potential by plating, therefore the adhesion of noble metallic plating to the mounting part can be easily avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a lead frame used in a plastic-sealed semiconductor integrated circuit device.

FIG. 1 shows a conventional lead frame used in a semiconductor integrated circuit device as described above. In FIG. 1, reference numeral 1 denotes a mounting part on which an integrated circuit chip is mounted, and this mounting part 1 is connected to a frame part 3 by a support part 2. Reference numeral 4azn designates external lead-out leads for leading out electrodes from the integrated circuit chip using thin gold wires.
-n are interconnected at their intermediate portions by left and right connecting portions 9a and 9b and are coupled to the frame portion 3. In the lead frame shown in FIG. 1, each of the above-mentioned parts is obtained by processing a metal plate into a desired pattern.

FIG. 2 (a>, (bl, (cl) shows a completed state in which the semiconductor integrated circuit device having the lead frame shown in FIG. Eggplant plastic enclosure 10
It is sized so that it is not exposed.

Generally, the coefficient of thermal expansion of plastic is larger than that of metal, and plastic expands due to moisture absorption. In the plastic-sealed semiconductor integrated circuit device described above, stress is generated between the plastic of the plastic enclosure and metal such as external leads due to expansion due to heat and moisture absorption. When the adhesive force is greater than the adhesive force between the plastic and the metal, a minute gap, that is, a micro gap, is generated between the plastic and the metal. The occurrence of this micro gap causes moisture to pass through it.
Harmful substances such as contaminant ions are induced into the integrated circuit chip portion, causing deterioration of the characteristics of the semiconductor integrated circuit device or causing fatal failures such as shorts and opens.

Normally, lead wires such as thin gold wires derived from integrated circuit chips have a thickness of 20 to 30 tons, and since soft metal materials such as gold and aluminum are used, there is a gap between the plastic and metal of the lead wire portion. The microgap is extremely small, so there is little risk of moisture permeation or intrusion of contaminant ions. Since the microcaps are exposed outside the plastic enclosure, the microcaps generated between the plastic enclosure and the support part 2 invite moisture, contaminant ions, etc. to enter along the support part 2 to the integrated circuit chip part, and the semiconductor It has the drawback of inducing failures such as deterioration of characteristics of integrated circuit devices, disconnections, and short circuits. Further, in the lead frame shown in FIG. 1, reference numeral 5 denotes a gold or silver plated portion 5 at the center of the lead frame. Since the tips of the external lead-out leads 4 a % n are connecting parts of thin gold wires, it is necessary to plate them with gold or silver. When bonding with adhesive or the like, there is no need for expensive gold or silver plating. However, since the mounting part 1 and the support part 2 are connected to the frame part 3 by the support part 2, the potential is the same as that of the external lead-out leads 4a to 4n, thereby avoiding adhesion of gold, silver, etc. The drawback was that it could not be done.

This invention eliminates the intrusion of moisture, contaminant ions, etc. through the support part that supports the mounting part on the frame body, which is the drawback of the conventional lead frame mentioned above, and also eliminates the intrusion of gold and silver into the mounting part and the support part. It is an object of the present invention to provide a lead frame for a semiconductor integrated circuit device that can eliminate the deposition of noble metal plating, thereby improving reliability and reducing manufacturing costs. In order to achieve this object, in the lead frame for a semiconductor device including the frame portion, the mounting portion, the external leads, and the connecting portion as described above, the mounting portion is coupled to the external leads through an insulator. This is what I supported.

Embodiments of the invention will be described below with reference to the drawings.

3 and 4 show a first embodiment of the invention. In FIGS. 3 and 4, reference numeral 6 indicates a lead 4 for connecting the mounting section 1 to the outside.
It is an insulator that combines with a plurality of a % n. The insulator 6 is made of a plate or film foil made of polyimide resin or the like, which adheres to the plastic enclosure and has a coefficient of thermal expansion and a coefficient of hygroscopic expansion similar to that of the plastic constituting the enclosure. 4 a % n is fixed by adhesive or thermocompression bonding over all or part of n. In this first embodiment, the support section that supports the mounting section 1 on the frame section 3 is cut and removed. The configuration of the first embodiment other than those described above is the same as the conventional one shown in FIG. 1, so the same components are given the same reference numerals in FIG. 3 as in FIG. 1, and the explanation thereof will be omitted.

Further, in order to make the insulator 6 clear, the exposed portion of the insulator 6 is shown with diagonal lines in FIGS. 3 and 5 (b) and (c).

In order to manufacture the lead frame according to the first embodiment of the present invention shown in FIGS. 3 and 4, first, as shown in FIG. 5 (A), a lead frame similar to that shown in FIG. As shown in FIG.
The insulator 6 is bonded or thermocompressed across all or part of the lower surface of the support part 2, as shown in FIG. 5(c).
It can be easily manufactured by cutting and removing.

Further, in the lead frame according to the first embodiment, in the plating process after formation, the mounting portion 1 is electrically isolated from the plating potential portion by VC, so that the mounting portion is plated with noble metals such as gold and silver. You can easily avoid getting caught.

As explained above, the lead frame of the first embodiment of the present invention does not have a support portion for supporting the mounting portion on the frame body portion, which is required in the conventional lead frame after formation of this type of lead frame.

Therefore, when a plastic-sealed semiconductor integrated circuit device as shown in FIGS. 2(a), (b), and (C) is constructed using the lead frame of this first embodiment, the support There are no micro-gaps between the plastic of the plastic envelope and the metal of the supporting part, which occurs along the parts, and the intrusion of harmful substances such as moisture and contaminant ions is minimized, improving the reliability of the integrated circuit device. performance and quality can be dramatically improved. In addition, in the plating process after forming the lead frame, the mounting section is electrically isolated from the plating potential section, making it easy to avoid precious metal plating on the mounting section, which reduces manufacturing costs. This has the advantage of contributing to the reduction of

FIG. 6 shows a second embodiment of the invention. This embodiment is suitable when it is necessary to heat the mounting section 1 from below when mounting an integrated circuit chip. That is, in the second embodiment, an insulator 8 made of the same material as in the first embodiment is fixed to the lower surface of a wide and short support section 7 extending from the mounting section 1 by adhesive or thermocompression bonding. These insulators 8 are provided so as to avoid the lower side of the mounting section 1. Note that the configuration of the second embodiment other than the above-mentioned is as follows.
Since it is the same as the first embodiment, the same components are given the same reference numerals in FIG. 6 as in FIG. 3, and the explanation thereof will be omitted. Further, in order to make the insulator 8 clear, the exposed portion thereof is shown with diagonal lines in FIG.

As explained above, the lead frame according to the second embodiment of the present invention can eliminate interfacial leakage between the plastic of the plastic enclosure and the metal constituting the support part, similarly to the first embodiment. There is an advantage that deposition of precious metal plating on the mounting portion and the support portion can be avoided.

As mentioned above, the lead frame for a semiconductor integrated circuit device according to the present invention can provide excellent moisture resistance as a finished product of an integrated circuit device using the lead frame, and can be used not only for ordinary integrated circuit devices but also for large scale devices. It can also be applied to integrated circuit devices, and has the effect of improving quality such as reliability and reducing manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional lead frame for a semiconductor integrated circuit device, and FIGS. 2 (a), (b), and (C) are a plan view, side view, and front view of a semiconductor integrated circuit device having a lead frame. 3 is an explanatory plan view of a lead frame for a semiconductor integrated circuit device according to the first embodiment of the present invention, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG.
(B) and (C) are plan explanatory diagrams showing the manufacturing method of a lead frame for a semiconductor integrated circuit device according to the first embodiment of the present invention in order of steps, and FIG. 6 is a semiconductor integrated circuit device according to the second embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Mounting part, 2... Supporting part, 3... Frame body part, 4
a to n...External lead-out lead, 5...Plated part, 6,
8...Insulator, 7...Wide, short mounting part, 9a
, 9b...Connecting portion, 10...Plastic enclosure. Patent applicant: Oki Electric Industry Co., Ltd. Figure 1 (a) (C) Figure 6 3 Procedural amendment November 25, 1980 Kazuo Chikusugi, Commissioner of the Patent Office, 1, Indication of the case, 1982, 1982, 1983 185587 No. 2, ji
*Relationship between lead frame for semiconductor integrated circuit device ^ and its l1ll manufacturing method 3, case of amending party Patent Applicant (OWE) Oki Electric AR, **Formal company 4, full text of attorney's specification and drawings Part of & [Description of Contents of Amendment 1, Title of Invention Lead Frame for Semiconductor Integrated Circuit Device and Method for Manufacturing the Same 2, Claims Lead Frame. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead frame used in a plastic-sealed semiconductor integrated circuit device and a method for manufacturing the lead frame. FIG. 1 shows a lead frame used in a conventional semiconductor integrated @wt device. In FIG. 1, reference numeral 1 denotes a mounting section on which all integrated circuit chips are mounted, and this mounting section 1 is connected to a frame section 3 by a support section 2. Reference numerals 4a to 4n are external lead-out leads for leading out electrodes from the integrated circuit chip using thin gold wires, etc. These external lead-out leads 4a to 4n extend radially from the vicinity of the mounting portion 1, and the external lead-out leads 4a to 4n are The middle part is the left and right connecting part 9a
, 9b, and are connected to the frame portion 3. The lead frame shown in FIG. 1 is obtained by processing a single metal plate so that the troughs form a desired pattern. Then, an integrated circuit chip is arranged and mounted on the mounting portion 1 of this lead frame, and this chip and external lead-out leads 4a to 4n are
The parts are electrically connected with pure gold wire, etc., and the part surrounded by chain lines in Fig. 1 is sealed with a plastic enclosure, and then the blank frame body part 3, connecting parts 9a, 9b, etc. are removed from the enclosure. Cut off unnecessary parts. FIGS. 2(a), (b), and (e) show the entire semiconductor integrated circuit device wt completed in this way, and are large enough so that the mounting portion of the lead frame is not exposed from the plastic enclosure 10 forming the enclosure container. It's in the middle of the day. Generally, the coefficient of thermal expansion of plastics is larger than that of metals, and plastics expand when they absorb moisture. In the plastic-sealed semiconductor integrated circuit device described above, stress is generated between the plastic of the plastic enclosure and metal such as external leads due to expansion due to heat and moisture absorption. When the adhesive force is greater than the adhesive force between the plastic and the metal, a minute gap, that is, a micro gap, is generated between the plastic and the metal. The occurrence of this micro gap causes moisture to pass through it.
Harmful substances such as contaminant ions are induced into the integrated circuit chip, causing deterioration of the characteristics of the semiconductor integrated circuit device or causing fatal failures such as shorts and opens.
r,! '-1. Normally, lead wires such as pure gold wires derived from integrated circuit chips have a thickness of 20 to 30 microns and are made of soft metal materials such as solid gold or aluminum. The micro gap between them is extremely small, so there is little risk of moisture permeation or intrusion of contaminant ions. Since the plastic enclosure is exposed outside the plastic enclosure, the micro gap generated between the plastic enclosure and the support part 2 is between the support part 2 and the plastic enclosure. This has the disadvantage that moisture, contaminant ions, and the like can enter along the line 152 up to the integrated circuit tip, leading to deterioration of the characteristics of the semiconductor integrated circuit device, and failures such as disconnections and short circuits. Also. In the lead frame shown in FIG. 1, numeral 5 is a gold plated or silver plated portion at the center of the lead frame. and,
Since the tips of the external lead-out leads 4a to 4n are bonded parts of pure gold wire, it is necessary to plate them with gold or silver. When bonding is carried out by methods such as bonding, there is no need for expensive gold or silver plating. However, since the mounting part 1 and the support part 2 are connected to the frame part 3 by the support part 2, the external lead-out leads 4a to 4n
The disadvantage is that it has the same potential as the metal and cannot avoid adhesion of gold, silver, etc. The present invention eliminates the intrusion of moisture, contaminant ions, etc. through the entire supporting part that supports the entire frame of the mounting part, which is caused by the drawbacks of the conventional lead frame mentioned above. A lead for a semiconductor integrated circuit device that can eliminate the deposition of precious metal plating such as gold or silver on the mounting portion and the support portion, thereby improving reliability and reducing manufacturing costs. The purpose of this invention is to provide a lead frame for a semiconductor device including a frame portion, a mounting portion, an external lead, and a connecting portion as described above. In this embodiment, the mounting portion is connected to and supported by the external lead through an insulator.Furthermore, the supporting portion is cut before being completely sealed with plastic. 3 and 4 show the first lead frame according to the present invention.
A plan view and a sectional view showing an embodiment are shown. In FIGS. 3 and 4, reference numeral 6 denotes an insulator that connects the mounting portion 1 to a plurality of external leads 4a to 4n. The insulator 6 is in contact with the plastic enclosure, is made of a plate or film foil made of polyimide resin, etc., and has a coefficient of thermal expansion and a coefficient of hygroscopic expansion similar to that of the plastic constituting the enclosure, and is connected to the mounting s1 and the external lead-out. All or part of the leads 4a to 4n are fixed by adhesive or thermocompression bonding. In this first embodiment, the frame portion 3 is mounted on the mounting portion 11.
The support part that supports it has been cut and removed. The configuration of the first embodiment other than those described above is the same as the conventional one shown in FIG. 1, so the same components will be described with the same reference numerals as in FIG. omitted. Further, for the sake of clarity, the exposed portions of the insulator 6 are shown with diagonal lines in FIGS. 3 and 5 (b) and (c). The entire lead frame K according to the first embodiment of the present invention shown in FIGS. 3 and 4 is first manufactured by a conventionally known method as shown in FIG. The entire lead frame (here treated as a frame material) is manufactured, and all or part of the mounting portion 1 and external leads 4a to 4n of this lead frame are manufactured as shown in Fig. 5←). The insulator 6 is bonded or thermocompressed to the lower surface of the support portion 2, and the support portion 2 is cut and removed as shown in FIG. 5(c). Note that this cutting and removal can be easily performed by a known method. After cutting and removal, complete plastic sealing is performed in the same manner as in the past, and unnecessary parts of the Fubhidashi-tomo frame are removed from the surrounding body. Further, in the lead frame according to the first embodiment, in the plating process after formation, the mounting portion 1 is electrically isolated from the part at the plating potential, so the mounting portion is plated with noble metals such as gold and silver. It is easy to avoid layering. As explained above, the lead frame of the first embodiment of the present invention does not have a support portion for supporting the mounting portion on the frame body portion, which was present in conventional lead frames of this type. Therefore, using the lead frame of this first embodiment,
When a plastic-sealed semiconductor integrated circuit device as shown in FIGS. 2(a), (b), and (c) K is constructed, the plastic of the plastic envelope generated along the supporting portion and the supporting portion There are no micro-gaps between all constituent metals, and the intrusion of harmful substances such as moisture and contaminant ions is minimized, making it possible to dramatically improve the reliability and quality of integrated circuit devices. 7t% In the plating process after forming the lead frame, the mounting part is electrically isolated from the part at the plating potential, and it is easy to prevent the precious metal from being plated onto the mounting part. ,
This has the advantage of contributing to a reduction in manufacturing costs. Is Fig. 6 a second embodiment of this invention? show. This embodiment is suitable for the case where it is necessary to heat the mounting section 1 from below when all integrated circuit chips are mounted. That is, in "Second Embodiment V", an insulator 8 made of the same material as in the first embodiment is fixed to the lower surface of the wide and short support part 7 extending from the mounting part 1 by contacting or thermocompression bonding. These insulators 8 are provided at the lower sound path of the mounting s1. Note that the configuration of the second embodiment other than those described above is the same as that of the first embodiment, so the same components are given the same reference numerals in FIG. 6 as in FIG. 3, and a description thereof will be omitted. Further, in order to make the insulator 8 clear, the exposed portion thereof is shown with diagonal lines in FIG. As explained above, the lead frame of the second embodiment of the present invention, like the first embodiment, can eliminate interfacial leakage between the plastic of the plastic enclosure and the metal constituting the entire support part. , there is an advantage that deposition of precious metal plating on the mounting portion and the support portion can be avoided. FIG. 7 shows a third embodiment of the invention. The symbols indicate the same things as in FIG. In the first embodiment, as shown in FIG. 5(C), almost all of the above-mentioned supporting part, that is, the connecting part connecting the chip mounting part 1 and the frame part (frame) 3 are removed. However, in this third embodiment, a portion of the support portion 2 is cut and removed. By simply cutting and removing a portion of the support portion 2 in this manner, the same effect as in the first embodiment can be obtained. That is, the remaining support part 2
Even if some harmful substances are exposed from the plastic enclosure and harmful substances enter through the micro-gaps mentioned above, the above-mentioned point 1
The chip is filled with plastic, which prevents harmful substances from entering the chip. It is obvious that the same effects as in the first embodiment can be obtained with respect to plating. As mentioned above, the present invention can provide excellent moisture resistance as a finished integrated circuit device, can be applied not only to ordinary integrated circuit devices, but also to large-scale integrated circuit devices, and is highly reliable. This has the effect of improving quality such as performance and reducing manufacturing costs. 4. Brief description of the drawings Fig. 1 is a plan view of a lead frame for a conventional semiconductor integrated circuit device r' (Fig. 2 (a), (b), and (c) is a semiconductor integrated circuit having a lead frame). Equipment flat] 14I
The figure, side view, front view, and FIG. 3 are the semiconductor integrated circuit device according to the first embodiment of the present invention? FIG. 4 is a plan view of the lead frame for the engine, FIG. 4 is a moving plane view along y-+vg in FIG. 3, and FIGS. 5 (a), (b), and (c) are according to the first practical example of this invention FIG. 6 is an explanatory plan view showing the method of manufacturing a lead frame for a semiconductor integrated circuit device in step 1111.1. FIG. The figure is an explanatory plan view of a lead frame according to a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Mounting part, 2... Supporting part, 3... Frame body part, 4
a~4n...External lead-out lead, 5...Plating %, f
i, 8...Insulator, 7...Support part, 9a+9b...
Connecting portion, 10... plastic enclosure. Patent applicant Okiichi Ki Kogyo Co., Ltd.

Claims (1)

[Claims] A frame body obtained by processing a metal plate into a required pattern, a mounting part on which an integrated circuit chip is mounted, a plurality of external leads extending radially from the vicinity of this mounting part, and an intermediate part of these external leads. a connecting part located at the top and connecting a plurality of external leads to each other, the plurality of external leads are coupled to the frame part by the connecting part, and the mounting part connects the plurality of external leads by an insulator. What is claimed is: 1. A lead frame for a semiconductor integrated circuit device, characterized in that the mounting portion is configured to have a size such that it is not exposed from a plastic enclosure constituting an enclosure for the semiconductor integrated circuit device.