JPH0521693A - Electronic device member and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing an electronic device member required for manufacturing an electronic device which is high in reliability, easily handled, and high in yield and an electronic device provided with the member concerned. CONSTITUTION:An insulating inorganic material film of silicon nitride or the like is applied to coat the surfaces of the stem 201 of a lead frame and a die 202 excluding a part 213 where a wire is bonded or a part of the die 202 connected to an electronic part 200, the stem 201 is made to extend over an electronic device and electrically connected to it with a gold wire 211, and all the electronic device and a part of the lead frame are enveloped in a molding material 203.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member for improving reliability of an electronic device in which an electronic component such as a semiconductor device is fixed on a member such as a substrate or a lead frame, and an electronic device having the member. The present invention relates to a device, a method for manufacturing the member, and the electronic device. Therefore, the present invention is characterized in that the substrate or the lead frame is covered with a protective film made of an inorganic material such as silicon nitride, except for a portion where an electronic component is die-attached and a portion where a gold wire bond is formed. And Then, when an electronic device is formed by using the member thus formed and an organic resin mold is applied, the adhesion between the member and the organic resin is improved.

Further, by improving the adhesion between the above-mentioned member and the protective film that adheres to the member, cracks and swelling (the mold material on the back side of the die are soldered to each other) generated between the member and the organic resin material. When heated by, for example, swelling due to vaporization of water in the vicinity of the die) to prevent cancer.

Another object of the present invention is to prevent defects caused by electrical contact between the lead frame and the electronic device.

[0004]

2. Description of the Related Art FIG. 1 shows a state of a package such as an integrated circuit manufactured by using a conventional technique. The lead frames 101 (105) and 102, particularly the die 102 to which the IC chip 100 is die-attached, is made of metal such as copper or 42 alloy, and a good conductor such as gold is printed on the front surface (back surface). ing. Then, when die-attaching the electronic component, the gold-silicon alloy 104 was formed at 300 to 400 ° C., and the IC chip was fixed on the die 102.

In addition to the above method, a method of using an organic material or a glass-based insulating material or silver paste heated to 100 to 400 ° C. is also known as a method of fixing the IC chip on the die. . That is, in the case of using an organic silver paste, a silver paste in which silver is mixed in a polyimide or epoxy organic resin is used as a fixing material, and is placed on the die 102 of the substrate or the metal lead frame. To I
Electronic parts such as C-chip were fixed. At this time, the fixing material 104 in a liquid state is solidified by a chemical reaction or a thermochemical reaction, so that the electronic component is mounted on a substrate or a lead.
Fix it on the dframe.

However, in any of the methods, when the surface treatment is performed by covering the surface with the mold 103 made of an organic resin after the fixing, the mold material and the material such as copper or 42 alloy are provided. The adsorbate 106 and the low-grade oxide 107, which are extremely easily peeled off, remain.

Therefore, as shown in FIG. 1, the plastic mold package is not only stored or used under severe conditions such as exposure to a high humidity atmosphere or use in water, but also normal storage.・ Even in use, water, which causes a decrease in reliability, travels through the adsorbate and lower oxides,
It penetrates into the inside of the mold material and gathers on the back surface of the die of the lead frame. When soldering (generally, dipping in molten solder at 260 ° C. for 3 to 10 seconds) is performed in this state, the water abruptly vaporizes and cracks 108, 1
09 and void 110 are generated.

Further, in the conventional method for fixing electronic parts by using an organic substance or its silver paste, this method is inexpensive and extremely excellent for mass production, but the organic substance fixing material 104 is used in the atmosphere. The vaporized components in the remaining organic material are adsorbed on the substrate or the die at room temperature or under heating (100 to 300 ° C.), and a protective film or mold resin formed after this is adsorbed. Deteriorates the adhesion with.

Further, as shown in FIG.
The de-on-chip (LOC) structure is a structure that allows the package chip to be made larger and highly integrated, but unlike the conventional structure in which a lead is present on the side surface of the package, Since there is a lead, there is a risk that the lead comes into contact with the chip surface and a short circuit or the like occurs. Therefore, in the LOC structure, an insulating tape is usually inserted between the chip and the lead,
Prevents contact between the tip and the lead. But,
This complicates the manufacturing process and causes mechanical damage to the chip due to contact between the insulating tape and the chip.
It goes without saying that a structure without insulating tape is desirable.

[0010]

SUMMARY OF THE INVENTION According to the present invention, such a conventional molded electronic component such as one or a plurality of semiconductor integrated circuits is provided on a substrate or a lead frame.
A method for preventing a decrease in reliability of an electronic device which is fixed by a method such as a gold-silicon alloy method, a glass-based silver paste method, or an organic material-based silver paste method and which requires high reliability. It is an object of the present invention to provide an electronic device provided with the above and an electronic device member necessary for the electronic device.

[0011]

SUMMARY OF THE INVENTION The above object is to provide a protective film made of an inorganic material on a member such as a substrate or a metal lead frame in an electronic device, which is required to be electrically connected (conductor). It is achieved by taking the configuration provided except the part. That is, by providing a protective film on the surface of the member, it is possible to improve the moisture resistance between the mold resin and the metal and also improve the adhesion. Furthermore, when the lead frame is covered with an insulating film except for a portion which is desired to be in direct contact with the IC chip or indirectly by a gold wire or the like, the insulating tape is interposed therebetween. Lead frame and IC without inserting
It is possible to prevent a short circuit or the like due to contact with the chip.

The present invention provides the above-mentioned member itself such as a lead frame and an electronic device incorporating the same, and a method for manufacturing the above-mentioned member and the electronic device.

A member such as a lead frame provided by the present invention is an inorganic material, such as silicon nitride, which is insulative and has good adhesion to the member except for a portion (conductor portion) where electrical connection is made. Silicon oxide, silicon carbide, DLC (characterized by being covered with a single layer or a multilayer film of diamond-like carbon,
As the manufacturing method, the following method can be used. That is, only the conductor portion in the member is previously covered with the cover film. Then, an inorganic material film is formed on the whole by plasma CVD method or sputtering method, and thereafter, the cover film and the inorganic material film thereon are simultaneously removed by lift-off method. Through this step, a member such as a lead frame is formed in which only the conductor portion is exposed and the other portion is covered with the inorganic material insulating film. The member thus formed can be used for manufacturing an electronic device in the same mass production process as before, without changing the process at all. When forming a lead frame die, the IC is placed on the die.
After fixing electronic parts such as chips by the conventional method, a cover film is placed on the electronic parts that are electrically connected by the wire bonding method (conductor parts on the electronic parts) or on the entire surface of the electronic parts. The same structure can be obtained by forming an inorganic material film on the entire surface by plasma CVD method or sputtering method and then removing the cover film and the inorganic material film on the inorganic material film by lift-off method at the same time. The member can be made. In particular, this method is effective when an organic material is used for fixing electronic parts, and the organic vaporized component as described above is covered with a mold while being adsorbed on the lead frame such as a die. Since it is not exposed, it is possible to prevent the reliability from decreasing. That is, even if the vaporized component is adsorbed to the lead frame or the like after fixing, it is exposed to vacuum in the subsequent film forming step, so that the vaporized component once adsorbed is removed,
Moreover, an insulating inorganic material film can be formed thereon.

FIG. 2 is a vertical sectional view of an IC package using the member having the structure of the present invention. Further, FIG. 3 shows an example of a manufacturing process of a member of the structure of the present invention, and FIG. 3E shows a drawing corresponding to the completed vertical section.

In FIG. 2, the lead frame die 20 is shown.
2 is provided with a chip 200 that is in close contact with a silver paste 204 or the like. The chip 200 may be an electronic component such as a capacitor or inductor other than the IC chip. The gold wire 211 is wire-bonded between the aluminum pad 212 of the chip 200 and the conductor portion 213 (here, gold-plated) that electrically connects the stem 201 of the lead frame.

The present invention is based on this lead frame die 20.
2 and the surface of the stem 201 are coated with an inorganic material 220 in advance so as to prevent the formation of organic or metal natural oxides which are likely to be produced when the electronic component 200 is brought into close contact with the die surface and the stem surface. . And
With metal, the adhesiveness of the organic resin mold material, which has poor adhesion, is positively utilized, and as a result, the adhesion between the lead frame and the molding material is improved. is there. In addition, the inorganic material film (insulating property) can prevent electrical contact between the lead frame and the electronic component, or between the lead frame.

In FIG. 2, the lead frame 201, 202 made of 42 alloy or copper is used as the electronic component 200.
The inorganic material insulating film 22 is attached to the portion to which the gold is printed on the portion to be attached and the portion to be wire-bonded.
0 is not formed. Further, although not shown in FIG. 2, it is possible to form a hole in the die 202 so that stress concentration due to thermal shock at the time of soldering is released. Finally, the electronic component 200 is fixed on the die 202, and after the wire bond is made between the stem and the electronic component by a gold wire, both the electronic component and the lead frame are encapsulated and completed.

An example of a method for producing the structure of the present invention will be described with reference to FIG. First, as shown in FIG. 3A, the stem 30 is formed by an organic resin or a mechanical method.
1 and the die 302 are fixed. At this time, the foot portion 305 of the lead frame may be in a state of being enclosed in an organic resin or the like as shown in the figure. Then, a gold coating 313 is selectively formed on a part of the stem 301 by a printing method or another method. This order may be reversed. That is, the gold film is first formed on the stem,
After that, the lead frame may be fixed.

Further, as shown in FIG. 3B, a film 322 of an organic resin or the like is formed by a screen printing method or the like on a portion of the stem and the die where the inorganic material insulating film is not desired to be formed. To do.

Furthermore, as shown in FIG. 3C, a protective film 320 made of an inorganic material is formed on the whole of these by a plasma CVD method or light C.
It is formed by a method such as a VD method or a sputtering method. At this time, it is particularly important when the LOC structure is produced by the method shown in FIG. 3 that the film formation is extremely well wraparound, and is almost evenly performed in any part, that is, good in step coverage. It is necessary. For example, the back side of the die 302 and the surface of the stem must be equally coated. Therefore,
For example, a method such as a vacuum deposition method is not suitable for this step.
As a matter of course, since the foot portion of the lead frame is in the organic resin, the inorganic material film is not formed on that portion.

This inorganic material film is required to have heat resistance and oxidation resistance so that it does not deteriorate even if left in the air at 500 ° C. for 1 hour. For this purpose, a material containing silicon oxide, silicon nitride, silicon carbide or the like as a main component is excellent.

Next, the so-called lift-off method of soaking the whole in an organic solvent and applying ultrasonic waves to dissolve away the organic resin film 322 and at the same time remove the inorganic material film formed thereon Thus, a portion to be die-attached with an electronic component later and a portion to be wire-bonded are exposed. Further, a fixing material 304 is applied on the die 302,
Further, the electronic component 300 is inserted and fixed onto it. Further, the electronic component and the stem are wire-bonded with the gold wire 311 to complete the internal wiring of the electronic device. Thus
FIG. 3D is obtained.

Finally, as shown in FIG. 3 (E), a mold 303 is formed by encapsulating the electronic components and the lead frame with an epoxy-based organic resin or the like to form a package 303 to complete the electronic device. To do. According to this step, in the lead frame, the inner part of the mold material can be almost completely covered with the inorganic material film, but the outer part has a part without the inorganic material film, It is convenient because the electronic device can be mounted in the same manner as a conventional one when mounted. Although the die 302 is present in the example shown in FIG. 3, the method shown in this example can be used even for a structure having no die.

In the method shown in FIG. 3, the lead frame is
Although the step of forming the film on the frame is performed after the assembly of the lead frame, it may be assembled after the film is formed on each of the lead frames.

As the inorganic material film, silicon oxide,
It is described as silicon carbide, silicon nitride, hard carbon, or a mixture thereof as a composition ratio, and a stoichiometric or non-stoichiometric monolayer or multilayer is suitable, but the thickness is Thirty
~ 500nm is desirable.

The present invention will be described below with reference to examples.

[0027]

[Embodiment 1] FIG. 4 shows an embodiment of the present invention.
Lead frame 43 in polyethylene liquefied by heating
0, the polyethylene is cooled and solidified, and the table 42
It was set to 1. At this time, a large number of lead frames can be mass-produced by forming a large number on one plane as shown in FIG. Further, a gold film 413 and an organic resin film 422 were formed on the conductor portion of the lead frame.
Thus, FIG. 4A was obtained.

Further, by the plasma CVD method,
A film of silicon nitride was formed on the surface of the dframe. A normal parallel plate type RF plasma CVD apparatus was used for forming the film, and disilane (Si2H6) and ammonia (NH3) were used as reaction gases. The reaction gases have a purity of 99.9 in all cases.
9% or more. In addition, argon (99.9% or more) was used as a gas for generating plasma. Figure 4
The disk-shaped substrate shown in (G) is placed on one electrode of the CVD apparatus, and the reaction chamber of the CVD apparatus is evacuated to -4 to -10 to -8 torr by a turbo molecular pump. Was held for 5 to 30 minutes to sufficiently exhaust unnecessary or harmful vaporizing components discharged from the organic resin or the like to the film formation reaction.

Thereafter, only argon gas was introduced into the reaction chamber, and high frequency power of 13.56 MHz was applied between the electrodes to generate plasma. As the high frequency power, 0.1 to 1 kW was suitable. After confirming that the plasma was stable, disilane and ammonia were introduced little by little into the reaction chamber to form a film. The ratio of the reaction gas was set to, for example, 1 part disilane and 5 parts ammonia.

The film formation was performed at room temperature. In this way, the lead frame has a thickness of 1 mm as shown in FIG.
It was coated with a silicon nitride film 420 having a thickness of 00 to 300 nm. The physical properties of the silicon nitride film obtained at this time have a withstand voltage of 8 MV / cm as compared with those formed on another substrate.
As described above, in the infrared absorption spectrum, the absorption peak of Si-N bond at 864 cm -1 was clearly confirmed, and it was confirmed that the refractive index was 2.0 and the resistance was sufficiently high.

Next, the whole lead frame was immersed in an organic solvent containing toluene as the main component while applying ultrasonic waves, and the organic resin film 422 and the silicon nitride film 420 thereon were removed by a lift-off method. The conductor portion 413 of the dframe is exposed. In this way, FIG. 4C was obtained.

Further, liquid polyethylene was poured to the level indicated by 425 in FIG. 4D and solidified. Then, the IC chip 400 was placed under the lead frame, and the lead frame and the IC chip were wire-bonded by the gold wire 411.

Furthermore, I on the surface of polyethylene
Epoxy synthetic resin 40 for C chip and lead frame
It was solidified by 3 to obtain FIG. 4 (E).

Finally, polyethylene is heated to melt,
Remove and harden the bottom of the IC chip with epoxy resin,
An IC device completely encapsulated could be produced.

[0035]

According to the present invention, the adhesion between a metal material such as a lead frame and a mold material is improved, and therefore, long-term storage, storage under high temperature and high humidity, and high-temperature treatment such as soldering. It was possible to reduce the defects associated with the above. Also, especially LO
As described above, in the electronic device having the C structure, the occurrence of defects such as a short circuit due to contact between the lead and the chip could be suppressed to a low level. The above increases the reliability of the electronic device itself.

In particular, as the chip area of the semiconductor integrated circuit increases, the packaging technology of the semiconductor integrated circuit is L
There is a tendency toward multilayering as represented by OC. However, in the extension of the prior art, the multi-layering requires complicated steps, and various problems pose a risk of damaging the function of the integrated circuit.

For example, in the conventional LOC technology, an insulating sheet is inserted between the IC chip and the lead frame, but this has a risk of mechanically destroying the IC chip as described above. In addition, if the adhesion between the mold material and the insulating sheet is poor, the occurrence of cracks, which has been a problem in conventional IC packages, becomes a problem with a higher probability.

On the other hand, as is apparent from the examples described in the present invention, even if the LOC structure is used, a structure other than the lead frame and the IC chip is not provided inside the molding material. The problem with the conventional LOC structure (including the insulating sheet) can be completely solved.

Not only the LOC structure, but also the LOC structure, only the inorganic material film is formed only on the boundary between the mold material of the lead frame and the outside. The reliability of electronic devices is greatly improved. Therefore, even if the LOC structure is included and the insulating sheet is contained inside, a film of an inorganic material is formed at the boundary between the mold material of the lead frame and the outside, and the lead frame is formed. If the adhesion between the rubber and the mold material is improved, the occurrence of cracks and the like is reduced, and thus the probability of defective products can be greatly reduced. The above discussion can be easily understood without any particular proof.

Furthermore, since the lead frame is coated with the inorganic material film at a relatively early stage of the manufacturing process, the handling in the subsequent process is not required to be subtle, and therefore the yield is high. Can be maintained. The formation of the film itself does not cause a large increase in cost because it can be performed in a large amount at a time as shown in the examples, and conversely, it is cheaper in consideration of yield and reliability.

Although the present invention has been described by taking the LOC structure as an example, other structures such as a chip-on-read (C
It will be clear that there is no problem adapting to those having the (OL) structure.

Further, in the present invention, a semiconductor element is shown as an example of the electronic component, but in addition, a hybrid IC in which a metal conductor is provided on an insulating substrate and a resistor and a capacitor are fixed to these may be used. The bonding may be not only wire bonding but also flip chip bonding or solder bump bonding.

As is clear from the above description, the present invention is believed to be extremely useful industrially.

[Brief description of drawings]

FIG. 1 shows an example of a package of a conventional semiconductor integrated circuit and its defects, and the package has a LOC structure.

FIG. 2 shows an example of a package of a semiconductor integrated circuit according to the present invention, wherein the package has a LOC structure.

FIG. 3 shows an example of a method for producing the package of the present invention.

FIG. 4 shows an example of a method for producing the package of the present invention.

[Explanation of symbols]

200 ... Electronic parts 201, 202, 205 ... Lead frame 203 ... Mold material 204 ... Fixing material 211 ... Gold wire 212 ... Aluminum pad 213 ... Gold contact 220 ... Inorganic material insulating film

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[Procedure amendment]

[Submission date] July 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 shows an example of a conventional semiconductor integrated circuit package and its defects, and the package has a LOC structure.

FIG. 2 shows an example of a package of a semiconductor integrated circuit of the present invention, which has a LOC structure.

FIG. 3 illustrates an example method of making the package of the present invention.

FIG. 4 illustrates an example method of making the package of the present invention.

FIG. 5 illustrates an example method of making the package of the present invention.

FIG. 6 illustrates an example method of making the package of the present invention.

[Explanation of symbols] 200 ... Electronic parts 201, 202, 205 ... Lead frame 203 ... Mold material 204 ... Fixing material 211 ... Gold wire 212 ... Aluminum pad 213 ... Gold contact 220 ... Inorganic material insulating film

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

Claims (11)

[Claims] 1. An electronic device in which a stem portion of a lead frame or an electronic device member having a function equivalent to that of the stem overlaps an electronic component. -Among the members for electronic devices having the same function as or the same as those of the electronic device, the part which is wire-bonded and the part where electronic parts are mounted are covered with the inorganic insulating material in the part sealed by the molding material. An electronic device characterized by the above. 2. The electronic device or the electronic device according to claim 1, wherein the inorganic insulating material is a material containing at least one of silicon carbide, silicon oxide, silicon nitride and carbon as a main component. Equipment member. 3. A lead frame in an electronic device or an electronic device member having a function equivalent to the lead frame, comprising:
In the portion existing in the mold material of the electronic device member having the same function as the dframe, the portion to be wire-bonded, the portion other than the portion to which the electronic component is mounted is covered with the inorganic insulating material, and A member for an electronic device, wherein a stem portion of the lead frame or a member for an electronic device having a function equivalent to that of the stem is overlapped on an electronic component in the electronic device. 4. The electronic device or the electronic device according to claim 2, wherein the inorganic insulating material is a material containing at least one of silicon carbide, silicon oxide, silicon nitride and carbon as a main component. Equipment member. 5. A lead frame in an electronic device or a member for an electronic device having a function equivalent to that of the lead frame, wherein at least a boundary portion between the portion covered with the mold and the outside is made of an inorganic insulating material. A member for an electronic device, which is covered. 6. The electronic device or the electronic device according to claim 3, wherein the inorganic insulating material is a material containing at least one of silicon carbide, silicon oxide, silicon nitride and carbon as a main component. Equipment member. 7. A coating of an organic resin or the like is formed on at least a portion to be wire-bonded and a portion electrically connected to an electronic component in a member for an electronic device having a lead frame or a function equivalent thereto. And a step of covering the entire electronic device member with a film made of an inorganic insulating material, and removing the film of the organic resin or the like and also removing the inorganic insulating film present thereon. A step of exposing the surface of the electronic device member, a step of electrically connecting the electronic device member and the electronic component, and a part of the electronic device member and the entire electronic component And a step of encapsulating the material in a material. 8. A step of forming a film of an organic resin or the like on at least a wire-bonding portion of a lead frame stem or an electronic device member having a function equivalent thereto, and the entire electronic device member. A step of covering the surface of the electronic device member with a film made of an inorganic insulating material, and removing the film of the organic resin or the like and also removing the inorganic insulating film present thereon. The step of placing the electronic device under the electronic device member, the step of electrically connecting the electronic device member and the electronic component, and a part of the electronic device member and the electronic component. And a step of encapsulating all of them in a molding material. 9. A stem of a lead frame stem or an electronic device member having a function equivalent thereto and a lead frame die or an electronic device member having a function equivalent thereto is present on the die. Then, the steps of arranging and fixing so as to overlap with each other, and at least a portion of the stem where wire bonding is performed and at least a portion of the die necessary for electrical connection with electronic components are coated with a film such as an organic resin. The step of forming, the step of covering the entire stem and die with a film made of an inorganic insulating material, removing the film of the organic resin or the like, and also removing the inorganic insulating film present thereon. A step of exposing the surface of the stem and the die, a step of fixing an electronic component on the die, and a step of electrically connecting the stem and the electronic component
And a step of encapsulating a part of the stem, the die, and the entire electronic component in a molding material. 10. A step of disposing and fixing an electronic device member having a lead frame or a function equivalent thereto,
A step of forming a film of an organic resin or the like on at least a wire-bonding portion of the lead frame; a step of covering the entire lead frame with a film made of an inorganic insulating material; And removing the inorganic insulating film present thereon to expose the surface of the lead frame, and arranging electronic parts under the lead frame. A step of electrically connecting the lead frame and the electronic component, and a step of enclosing a part of the lead frame and the entire electronic component in a molding material. A method for manufacturing an electronic device having: 11. A step of fixing a foot frame of an electronic device member having a function equivalent to that of a lead frame by immersing it in a liquid organic resin or the like and solidifying the liquid organic resin. , A step of forming a film of an organic resin or the like on at least the wire-bonded portion of the lead frame, and the entire lead frame except for the foot portion in the organic resin is made of an inorganic insulating material. A step of covering with a film made of, and removing the film of the organic resin or the like,
A step of removing the inorganic insulating film present thereon to expose the surface of the lead frame; a step of disposing an electronic component under the lead frame; A step of electrically connecting the dframe and the electronic component;
A method of manufacturing an electronic device, comprising the step of encapsulating a part of the dframe and the whole of the electronic component in a molding material.