JP2796343B2 - Semiconductor device or semiconductor integrated circuit device and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To prevent tab short-circuit, chip short-circuit or short-circuit between wires due to film damage caused by thermal deterioration of a coating film by a method wherein the coating film of a covered wire is specific heat-resistant polyurethane while an end of the covered wire is connected to an external terminal of a semiconductor chip and the other end is connected to a lead. CONSTITUTION:An insulating coating film 5B of a coating wire 5 comprises heat-resistant urethane wherein polyol component and isocyanate are reacted and a structure unit induced from terephthalic acid is contained in a molecular skeleton. An end of the covered wire 5 is connected to an external terminal 2C of a semiconductor chip 2 and the other end is connected to a lead 3. Since film damage of a coating film comprising heat-resistant polyurethane which is caused by thermal deterioration can be thus prevented, electrical short-circuit problems such as tab short-circuit, chip short-circuit and short-circuit between wires can be prevented..

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device manufacturing technique, and more particularly, to an external terminal and a lead of a semiconductor chip by a coated wire in which the surface of a metal wire is coated with an insulating coating film. And a technology effective when applied to a semiconductor device obtained thereby.

Further, the present invention relates to a structure of a semiconductor device having a highly integrated and highly functional semiconductor chip, and more particularly to a technology effective when applied to improvement of connection reliability by wire bonding.

[Conventional technology]

Generally, a wire made of, for example, gold (Au), aluminum (Al), or copper (Cu) is used to electrically connect external terminals (bonding pads) of semiconductor chips and leads (inner leads) in a semiconductor device. Used.

Conventionally, as this kind of wire, a so-called bare wire consisting only of a metal wire of the above-mentioned material has been used, but recently, in order to prevent a short circuit between the wires, a surface of the metal wire is coated with an insulating film. It is contemplated to use a coated wire coated with.

Regarding the use of such a coated wire, for example, JP-A-57-152137, JP-A-57-162438, JP-A-60-224237,
Nos. 61-194735 and 61-186239.

According to these known techniques, urethane resin or nylon resin (JP-A-57-152137), polyimide resin, polyurethane resin, or fluorine-based resin (JP-A-57-162438) is used as a material of a coating insulating film of a coating wire. No.),
Polyethylene resin, polyimide resin or urethane resin (Japanese Patent Application Laid-Open No. 60-224237), urethane resin, polyvinyl chloride resin or polyimide resin (Japanese Patent Application Laid-Open No. 61-194735), and insulating varnishes such as enamel, formal, and polyester Resin or polyurethane resin
No. 61-186239).

Further, as an example describing this type of technology, see Nikkei McGraw-Hill, published on June 11, 1984, “Micro Devices (Nikkei Electronics Separate Volume),” p.
There are 92.

In the above document, an epoxy sealant in a resin mold type semiconductor device, that is, a resin composition (hereinafter, simply referred to as “resin”) is described in detail.

That is, due to the demand for high-density mounting, the package size of a semiconductor device tends to be gradually reduced. However, when a highly integrated semiconductor chip as described above is sealed in a miniaturized package, the package thickness and package The length is necessarily small.

As a result, cracks easily occur due to the difference in the coefficient of thermal expansion between the resin (resin composition) constituting the package and the lead. In addition, since the package is small even without cracks, moisture easily penetrates from the outside through the leads that lead out, which promotes corrosion of external terminals on the semiconductor chip. There is a concern that this will happen.

That is, the thermal expansion coefficient of a general epoxy resin is 17 ×
10 ^-6 ~70 × 10 ^-6 / ℃ greatly, thermal expansion coefficient of about 10 × 10 ^-6 of Fe-Ni alloy constituting the lead contrast, 42 alloy, a kovar about 6 × 10 ^{- 6} and small.

Due to such a difference in the coefficient of thermal expansion, interface peeling, so-called cracking, occurs at the contact portion with the lead after the package is cured, and the situation that the moisture resistance of the semiconductor device is reduced has occurred.

In order to suppress the occurrence of the cracks, a filler having an extremely small coefficient of thermal expansion, such as fused silica powder, has been blended into the resin.

[Problems to be solved by the invention]

However, the present inventor has found that all of the above-mentioned known techniques have the following problems.

That is, the present inventors have conducted intensive research and found that among the materials of the coating film disclosed in the above-described known technology,
Polyester resin is not optimal because the rigidity of the film is too large and the bonding property is poor, and there is a possibility that poor bonding may occur.

In addition, including polyester resin, polyimide resin (nylon resin), fluorine resin, polyethylene resin,
Polyvinyl chloride resin and enamel are not sufficiently satisfactory in the following points. That is, these materials
For example, since carbonization occurs without being decomposed at the heating temperature at the time of forming the metal ball, carbide attached to the coated wire at the time of wire bonding to the external terminal of the semiconductor chip is caught by the capillary and hinders the supply of the wire,
Carbide, which is a conductive material, falls on the circuit forming surface of the semiconductor chip to cause a short circuit.In addition, the bonding property is poor due to poor peeling of the coating film during wire bonding to the lead. Attempting to remove it results in carbonization by heating, which makes it difficult to remove the carbide and hinders bonding.

Furthermore, although polyurethane (or urethane) resin and formal have generally better properties than the other materials described above, according to experiments performed by the present inventors, particularly due to insufficient heat resistance, It has been found that a problem of thermal deterioration occurs. That is, when the semiconductor device is used after being mounted, the wires also receive a considerably large thermal shock due to the heat generated by the semiconductor element. Therefore, even if it is a coated wire, if a general polyurethane resin or formal is used as the coating film, if the wire has a tab touch state, a touch state on the silicon region of the chip, and a touch state between the wires, It has been confirmed by the present inventors that the temperature cycle test and high-temperature storage test of MIL-883B conducted by polyurethane and formal cause thermal degradation, and eventually cause tab shorts, chip shorts, and even shorts between wires due to film destruction. It was done.

Regarding this, in any of the above-mentioned known techniques, no consideration has been given to the problem of thermal deterioration in the polyurethane resin coating film. Cannot be used under the conditions of use and the test conditions of MIL-883B, so that there is a problem that short-circuit failure occurs as described above.

Although the coefficient of thermal expansion of the entire resin decreases in proportion to the amount of the filler, the viscosity of the resin increases in inverse proportion thereto, and it is found that the flow (deformation) of the wire occurs in the resin molding process. Was.

That is, with the flow of the wires, contact between the wires, contact between the wires and the tab, or between the wires and the semiconductor chip occurs, and the reliability as a semiconductor device is significantly reduced due to an electric short circuit.

Therefore, in the above prior art, the content of the filler in the resin must be reduced to 60% by weight or less, and it is practically difficult to approximate the thermal expansion coefficient to the thermal expansion coefficient of the lead.

Further, if the package is formed while the wire is in contact with the tab or the semiconductor chip, the wire is broken due to the deformation accompanying the thermal expansion of the package, and the electrical reliability of the semiconductor device is reduced. Had become.

Also, DIP (D ual I n- line P ackage) resin-sealed semiconductor device, such as is connected to the lead of the inner leads of the external terminals of the semiconductor chip (bonding pads) with a wire. In this resin-encapsulated semiconductor device, a semiconductor chip, inner leads and wires are sealed with resin (resin molding). As the resin, for example, an epoxy resin is used.

The resin-encapsulated semiconductor device being developed by the present inventors uses a coated wire as a wire as described in Japanese Patent Application No. 62-200561 previously filed by the present applicant. The coated wire is formed by coating the surface of a metal wire with an insulator. The metal wire of the coated wire is formed of gold (Au), copper (Cu), aluminum (Al), or the like. The insulator is formed of a resin material such as a polyurethane resin or a polyimide resin. The covered wire is bonded by a ball & wedge bonding method or a wedge & wedge bonding method.

A resin-encapsulated semiconductor device using a covered wire prevents short-circuits due to contact between adjacent wires, short-circuits due to contact between wires and ends of semiconductor chips, and short-circuits due to contact between wires and tab ends. In addition, there is a feature that electrical reliability can be improved. The above-mentioned short circuit is particularly likely to occur due to the flow of the resin injected in the resin sealing step.

The present inventor has found the following problems during the electrical characteristic inspection of the resin-encapsulated semiconductor device using the above-described covered wire.

The coated wire has no short circuit between adjacent coated wires and no short circuit between the coated wire and each of the semiconductor chip and the tab end. On the other hand, the resin-encapsulated semiconductor device under development by the present inventors has a large tab size so that semiconductor chips of different sizes (different functions) can be mounted on the same package. Therefore, the resin-encapsulated semiconductor device allows the contact between the covering wire and the corner of the tab or the corner of the lead. However, when a resin film such as a polyurethane resin is used as an insulator of the coated wire,
Both the adhesiveness between the metal wire and the insulator and the adhesiveness between the insulator and the resin (epoxy resin) as the sealing material are high. That is, the shrinkage stress generated in the sealing material in the temperature cycle after the resin sealing is applied to the entire area of the metal wire of the coated wire, and the stress is particularly concentrated on the coated wire in the portion in contact with each corner described above. For this reason, there has been a problem that the insulator of the coated wire is broken and the metal wire and the tab are short-circuited, or the coated wire is broken, and the electrical reliability of the resin-encapsulated semiconductor device is reduced. In particular, the lead frame of the above-described resin-encapsulated semiconductor device is formed by punching, and burrs are generated on the respective end surfaces of the tab and the lead. Therefore, when the burrs come into contact with the covering wire, the above-described problem becomes remarkable. . This problem also occurs when the covering wire comes into contact with a corner of the semiconductor chip.

Prior to the development of the above-mentioned resin-sealed semiconductor device, the present inventor has found the following problems.

The pin arrangement (position and arrangement of signal pins and power pins) of the resin-sealed semiconductor device may vary depending on the type of board to be mounted and the type of external device. In such a case,
It is necessary to develop a resin-sealed semiconductor device having another pin arrangement having the same function. That is, it is necessary to newly develop the arrangement of the external terminals of the semiconductor chip and the arrangement of the leads of the package. In particular, the development of a semiconductor chip is about 10 times higher than that of a package.Therefore, there is a problem that the development cost becomes very high to develop a new resin-encapsulated semiconductor device simply by different pin arrangement. Was.

One object of the present invention is to provide a technology that can prevent a tab short, a chip short, or a short between wires due to film destruction due to thermal deterioration of a coating film in a semiconductor manufacturing technology using a coated wire. It is in.

It is another object of the present invention to provide a semiconductor manufacturing technology using a covered wire, which can ensure the bonding property of the covered wire, particularly the bonding strength between the covered wire and the lead.

It is another object of the present invention to provide a technique in a semiconductor manufacturing technique using a covered wire, which can perform bonding without causing a bonding failure by a normal wire bonding technique.

Another object of the present invention is to provide a technology that can improve the reliability of a semiconductor device in a semiconductor technology using a covered wire.

Still another object of the present invention is to provide a technique capable of realizing a multi-terminal semiconductor device in a semiconductor technique using a covered wire.

Another object of the present invention is to prevent a crack at an interface with a component such as a semiconductor chip and a lead in a resin constituting a package.

Another object of the present invention is to prevent breakage of a wire caused by thermal stress on a package.

Another object of the present invention is to provide a technique capable of preventing breakage of an insulator of the covered wire or disconnection of the covered wire in a semiconductor device using the covered wire, thereby improving electrical reliability. It is in.

Another object of the present invention is to provide a technique capable of reducing the development cost of a semiconductor device using a covered wire.

Another object of the present invention is to provide a resin-encapsulated semiconductor device having excellent releasability from a mold.

Another object of the present invention is to provide a method of dicing (pelletizing) a wafer suitable for bonding using a covered wire.

Another object of the present invention is to provide a resin-sealed semiconductor device suitable for surface mounting.

Another object of the present invention is to facilitate manufacture of a thin resin-sealed semiconductor device.

[Means for solving the problem]

The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.

In the semiconductor device of the present invention, the manufacturing technology and the semiconductor device obtained thereby, the insulating coating film of the coated wire, the polyol component and isocyanate react,
It is made of a heat-resistant polyurethane containing a structural unit derived from terephthalic acid in its molecular skeleton. One end of the covering wire is connected to an external terminal of the semiconductor chip, and the other end is connected to a lead.

The coating film on the one end side of the coating wire is removed at the time of forming the metal ball, or is connected to the external terminal of the semiconductor chip without forming the metal ball.

The other end of the coated wire is brought into contact with a lead to break the coating at the contact portion, or by previously removing the coating at the other end, thereby forming the other end of the coated wire. The metal wire on the side is connected to the lead.

When connecting the other end of the covered wire to the lead, only the wire bonding portion of the lead can be heated.

A predetermined amount of a coloring agent can be added to the coating film of the coating wire.

Further, in another semiconductor device manufacturing technique of the present invention and the semiconductor device obtained thereby, the insulating coating film of the coated wire is deteriorated by reducing the number of times of coating film destruction after 100 hours at 150 ° C. to 175 ° C. It can be formed of a non-carbonized material at a rate of not more than 20% and at the time of forming metal balls or removing the coating film.

Further, the outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, first, an intermediate layer made of an insulating resin is provided between a metal wire and a resin, and a resin-encapsulated semiconductor device structure in which the thermal expansion coefficient of the resin is controlled to 10 × 10 ⁻⁶ / ° C. or less. Things.

Second, a resin-encapsulated semiconductor device in which external terminals on a semiconductor chip and leads are connected by a metal wire having an intermediate layer made of an insulating resin around the lead, and the periphery thereof is molded with a resin. Total diameter of wire and intermediate layer is 30μm
The thermal expansion coefficient of the resin is 10 × 10 ⁻⁶ /
A resin-sealed semiconductor device structure controlled at a temperature of not more than ° C.

Third, a metal wire for connecting an external terminal and a lead formed on a semiconductor chip is formed around a first intermediate layer made of an insulating resin, and is formed on an outer periphery of the first intermediate layer. A resin-encapsulated semiconductor device structure including a second intermediate layer formed of a resin.

Fourth, when connecting a metal wire between the external terminal and the lead on the semiconductor chip, one end of the metal wire protruding from the tip of the bonding tool to which the ultrasonic vibration is applied is connected to the external terminal. After crimping, the bonding tool is moved while maintaining the ultrasonic vibration, a metal wire is sent out from the tip, and the other end of the metal wire is joined to the lead, and then the coefficient of thermal expansion is 10 × 10 ^−6. This is to mold the range of connection by the metal wires using a resin controlled to not more than / ° C.

Fifth, a polyol component and an isocyanate are allowed to react around a metal wire, and an insulating layer made of polyurethane containing a structural unit derived from terephthalic acid is applied to a molecular skeleton to form an intermediate layer. After connecting the external terminals of the semiconductor chip and the leads with the wires, molding is performed with a resin whose coefficient of thermal expansion is controlled to 10 × 10 ⁻⁶ / ° C. or less for the connection range.

Sixth, after forming an intermediate layer made of an insulating resin around a metal wire to obtain a wire, the wire is used to connect a semiconductor chip mounted on a lead frame to a lead, and the lead frame is connected. Is placed in a mold in which a plurality of cavities are formed, and a high-pressure molten resin is injected from at least two or more resin sources into the plurality of cavities of the mold to form a package. Things.

Seventh, an intermediate layer forming apparatus for forming first and second intermediate layers around a metal wire, comprising a first storage tank and a second storage tank arranged continuously, The storage tank has a pulley rotatable in a vertical plane, the lowermost part of the pulley is immersed in the storage liquid, and a predetermined amount of the storage liquid assembled by the pulley at the uppermost part of the pulley. Has an intermediate layer forming device structure in which the first or second intermediate layer is formed around the metal wire in contact with the metal wire.

Further, among the inventions disclosed in the present application, the outline of a representative one will be briefly described as follows.

(1) In a semiconductor device in which external terminals and leads of a semiconductor chip mounted on a tab are connected by a covering wire, and the covering wire and a connecting portion of the covering wire are covered with a resin, the covering wire extends. The shape of the corner of the semiconductor chip, the corner of the tab, or the corner of the lead is reduced.

(2) The covering wire is extended so as not to contact the corner of the semiconductor chip, the corner of the tab, or the corner of the lead.

(3) A method of forming a semiconductor device using a covered wire, wherein a semiconductor chip is mounted at a chip mounting position of a first package, and an external terminal and a lead of the semiconductor chip are connected to each other by a covered wire. Forming the device, this first
A semiconductor chip identical to the semiconductor chip of the first semiconductor device is mounted on a chip mounting position of a second package of a type different from that of the first package of the semiconductor device, and external terminals of the semiconductor chip and leads are connected by a covering wire. To form a second semiconductor device.

(4) A method for forming a semiconductor device using a covered wire, comprising: mounting a first semiconductor chip at a chip mounting position of a lead; connecting an external terminal of the first semiconductor chip to the lead with the covered wire; Forming a first semiconductor device by encapsulating the first semiconductor device, and mounting the first semiconductor device at a chip mounting position of the same lead as the lead of the first semiconductor device.
A second semiconductor device is mounted on which a second semiconductor chip of a type different from the semiconductor chip is mounted, and external terminals and leads of the second semiconductor chip are connected with a covering wire and then sealed with a resin to form a second semiconductor device. A method for forming a semiconductor device.

[Action]

According to the above-described means, the coating film made of heat-resistant polyurethane is prevented from causing film destruction due to thermal deterioration.
Alternatively, it is possible to prevent an electrical short failure such as a short between wires.

In addition, the heat-resistant polyurethane as the insulating coating film of the wire can be bonded by decomposing the urethane bond even at the bonding temperature or ultrasonic vibration energy at the time of normal wire bonding. Reliable bonding can be obtained in combination with ultrasonic vibration or ultrasonic vibration. In this case, if local heating of the bonding site is used together, more reliable wire bonding can be performed.

Furthermore, as an insulating coating film of a coated wire,
By using a non-carbonized material when forming metal balls or removing the coating film, the degradation rate of the coating film after 100 hours at 75 ° C is less than 20%. Since deterioration can be prevented, it is possible to prevent electrical short-circuit failure due to film destruction.

According to the first means described above, the coefficient of thermal expansion of the resin is
By controlling the temperature to 10 × 10 ⁻⁶ / ° C. or less, it is possible to effectively prevent the occurrence of cracks due to the difference in the coefficient of thermal expansion between the lead and the like. In addition, the viscosity of the resin increases in a state where the coefficient of thermal expansion is suppressed as described above. However, since the intermediate layer made of an insulating resin is provided around the metal wire, an electrical short circuit due to a wire flow in the resin molding process is provided. Is effectively prevented.

According to the second means, the total diameter of the metal wire and the intermediate layer is 30 μm.
m or less, it is difficult for the wire flow due to the resin injection pressure in the resin molding process to occur, and even if the wire flow occurs, an intermediate layer formed of an insulating resin is provided around the metal wire. Therefore, an electrical short circuit is effectively prevented.

According to the third means, since the first intermediate layer made of an insulating resin and the second intermediate layer having good releasability around the first intermediate layer, the wire is in contact with the semiconductor chip. Even in the state, since the metal wire can be finely moved by the releasing action of the second intermediate layer, disconnection can be effectively prevented without applying unreasonable stress to the metal wire itself.

According to the fourth means, when the metal wire is sent from the bonding tool, the application of the ultrasonic vibration is continued in the bonding tool. Is prevented from being deformed.

According to the fifth means, since the intermediate layer structure is not carbonized by heating during the formation of the metal ball during wire bonding, contamination of the semiconductor chip during wire bonding can be effectively prevented. Further, since the coefficient of thermal expansion is kept low, cracks due to the difference in coefficient of thermal expansion are prevented.

According to the sixth means, since the molten resin is injected into the plurality of cavities from two or more resin supply sources, the molten resin having a relatively high viscosity can be injected into the cavities with high efficiency. An efficient resin molding process can be realized for a lead frame connected with a wire having a layer.

According to the seventh means, by arranging the first storage tank and the second storage tank continuously, it is possible to continuously and easily form the first and second intermediate layers.

According to the above-mentioned means (1), the concentration of the stress due to the shrinkage of the resin on the covering wire at the corner contacting the corner of the semiconductor chip, the corner of the tab, or the corner of the lead is reduced. It is possible to prevent a short circuit between the semiconductor chip or the tab and the metal wire of the covered wire due to breakage of the body, or disconnection of the covered wire. As a result, the electrical reliability of the semiconductor device can be improved.

According to the means (2), since the stress based on the shrinkage of the resin does not concentrate on the covering wire, a short circuit between the semiconductor chip or the tab and the metal wire of the covering wire due to breakage of the insulator can be prevented.
Alternatively, disconnection of the covered wire can be prevented. As a result, the electrical reliability of the semiconductor device can be improved.

According to the means (3), the external terminals of the semiconductor chip and the leads are connected with the covering wires across the other leads,
Alternatively, since the external terminals and the leads of the semiconductor chip can be connected by crossing the covering wires, a plurality of types of semiconductor devices can be used using the same semiconductor chip (standardization of the semiconductor chip) and using different types of packages. Can be formed. As a result, since the development cost of the package is lower than the development cost of the semiconductor chip, many types of semiconductor devices can be formed at a low development cost.

According to the means (4), the external terminal of the semiconductor chip and the lead are connected with the covering wire across the other leads,
Alternatively, since the leads and the external terminals of the semiconductor chip can be connected by crossing the covering wires, the same lead (lead frame) is used (lead frame standardization) and a plurality of semiconductor chips of different types are used. Various types of semiconductor devices can be formed. As a result, it is not necessary to develop a lead every time a semiconductor chip is developed (for example, for each semiconductor chip having the same function but different external terminal positions), so that various types of semiconductor devices can be formed at a low development cost. Can be.

〔Example〕

In the following description of the invention, for convenience, the embodiments are divided into the embodiments 1 to 6. However, these are not separate inventions, and can be replaced with each other, and one embodiment is a part of another embodiment. Is a deformation process or a deformation structure.

(1) Example 1 Next, the heat-resistant polyurethane used in the coating film of the coated wire in the present invention will be further described. This heat-resistant polyurethane is obtained by reacting a polyol component with an isocyanate, and has a terephthalic acid as a molecular skeleton. This heat-resistant polyurethane is obtained using a polymer component mainly composed of a terephthalic acid-based polyol containing active hydrogen, and an isocyanate. Here, “consists of a main component” is intended to include a case where the whole is composed only of a main component.

Terephthalic acid-based polyol containing the active hydrogen, terephthalic acid and polyhydric alcohol, using OH-CO
OH = 1.2-30, the reaction temperature is set to 70-250 ° C., and it can be obtained by a conventional esterification reaction. In general, those having an average molecular weight of 30 to 10,000 and having about 100 to 500 hydroxyl groups and having hydroxyl groups at both ends of the molecular difference are used.

Raw materials constituting such a terephthalic acid-based polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Hexane glycol, butane glycol, glycerin,
Aliphatic glycols such as trimethylolpropane, hexanetriol and pentaerythritol;
In addition, polyhydric alcohols such as 1,4-dimethylolbenzene can be mentioned. In particular, it is preferable to use ethylene glycol, propylene glycol, and glycerin.

Terephthalic acid is used as the dicarboxylic acid. If necessary, amic acid and imidic acid can be used in combination.

 The structural formula of the imidic acid is as follows.

Further, dibasic acids such as isophthalic acid, orthophthalic acid, succinic acid, avidisoic acid and sebacic acid, 1,2,3,4-butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, ethylene Polybasic acids such as tetracarboxylic acid, pyromellitic acid and trimellitic acid may be used in combination.

As the isocyanate to be reacted with the terephthalic acid-based polyol, the isocyanate group of a polyvalent isocyanate having at least two isocyanate groups in one molecule, such as toluylene diisocyanate and xylylene diisocyanate, is converted into a compound having active hydrogen, for example, phenol. And those blocked with caprolactam and methyl ethyl ketone oxime.
Such isocyanates are stabilized. Further, there may be mentioned those obtained by reacting the above-mentioned polyvalent isocyanate compound with a polyhydric alcohol such as trimethylolpropane, hexanetriol or butanediol and blocking with a compound having active hydrogen.

Examples of the isocyanate compound, manufactured by Nippon Polyurethane Co., Millionate MS-50, Coronate 2501,250
3, 2505, Coronate AP-St, Death Module CT-St and the like. It is preferable to use a polyisocyanate having a molecular weight of about 300 to 10,000.

In the present invention, a coating composition is prepared using the above-described raw materials, and this is applied to a metal wire of a wire main body, and 0.5 to several μm is applied.
By forming a film having a thickness of m, a semiconductor device is manufactured using a covered wire insulated from a metal wire of a wire main body.

The coating composition used in the present invention is prepared by adding an isocyanate group of the stabilized isocyanate of 0.4 to 4.0 equivalents, preferably 0.9 to 2.0 equivalents and a required amount of a curing acceleration catalyst per equivalent of the hydroxyl group of the polyol component, and further adding an appropriate amount of an organic compound. It can be obtained by adding a solvent (phenols, glycol ethers, naphtha, etc.) to make the solid content usually 10 to 30% by weight. At this time, if necessary, an appropriate amount of an additive such as an appearance improving agent and a dye can be blended.

In the present invention, the isocyanate group of the stabilized isocyanate is 0.4 to 0.4 per hydroxyl equivalent of the polyol component.
The reason for adding 4.0 equivalents is that if it is less than 0.4 equivalents, the crazing characteristics of the resulting insulated wire will decrease, while the wear resistance of the coating film exceeding 4.0 equivalents will be inferior. The curing acceleration catalyst added at the time of preparing the coating composition is preferably 0.1 to 10 parts by weight per 100 parts by weight of the polyol component. When this is less than 0.1 part by weight, the tendency to deteriorate the film-forming ability as well as the curing promoting effect is reduced,
Conversely, if the amount exceeds 10 parts by weight, the heat-resistant urethane bonding wire obtained will have reduced thermal degradation characteristics.

Examples of the curing acceleration catalyst include metal carboxylic acids, amino acids, and phenols.Specifically, naphthenic acid, octenoic acid, zinc salts such as persatic acid, iron salts, copper salts, manganese salts, cobalt salts, A tin salt, 1,8-diazabicyclo (5,4,0) undecene-7,2,4,6 tris (dimethylaminomethyl) phenol is used.

The insulated coated bonding wire used in the present invention can be obtained by applying the above-described coating composition on the surface of the metal wire of the wire main body and baking it with a conventional baking coating device.

The coating and baking conditions vary depending on the amounts of the polyol component, the stabilized isocyanate, the polymerization initiator and the curing accelerator, but are usually about 200 to 300 ° C. for about 4 to 100 seconds. In short, baking is performed at a temperature and for a time sufficient to substantially complete the curing reaction of the coating composition.

The insulating coated bonding wire thus obtained has an insulating coating film made of heat-resistant polyurethane formed on the outer periphery of a metal wire of a wire body made of gold, copper or aluminum.

In this case, a composite coating film structure using the insulating coating film and another insulating coating film in combination may be used. This composite coating film, after forming the insulating coating film of the present invention described above,
It is obtained by further forming a second insulating coating film on the insulating coating film. In this case, the thickness of the second insulating coating film is not more than twice the thickness of the insulating coating film of the present invention,
Preferably, it is set to 0.5 times or less. Examples of the material for forming the second insulating coating film include a polyamide resin, a special polyester resin, and a special epoxy resin.

Hereinafter, the configuration and operation of the present invention will be described together with an example in which the present invention is applied to a semiconductor manufacturing technique used for a resin-encapsulated semiconductor device.

In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and redundant description thereof will be omitted.

FIG. 1 is a half sectional view of a resin-encapsulated semiconductor device which is I of Embodiment 1 of the present invention, FIG. 2 is a schematic enlarged sectional view of a wire bonding portion, and FIG. FIG. 4 is a schematic perspective view of a main part of the wire bonding apparatus, FIG. 5 is a partial sectional view showing a specific configuration of a main part of the wire bonding apparatus, and FIG. 6 is an arrow in FIG. FIG. 7 is a plan view as seen from the direction VI, and FIG.
FIG. 8 is a schematic configuration view showing the principle of forming metal balls, FIG. 9 is an exploded perspective view of a main part of a spool of the wire bonding apparatus, and FIG. 10 is an enlarged view of a main part of the spool. Perspective view, FIG. 11 is a schematic plan view of a local heating unit for wire bonding, FIG. 12 is a plan view showing an example of wire bonding, FIG. 13 is a partial cross-sectional view showing a chip touch state of a covering wire, FIG. FIG. 14 is an enlarged partial cross-sectional view showing the chip short state, FIG. 15 is a partial cross-sectional view showing the tab touch state of the coated wire, FIG. 16 is an enlarged partial cross-sectional view showing the tab short state, and FIG. FIG. 18 is a graph showing the short-circuit rate between the semiconductor chip and the coated wire with respect to the temperature cycle, and FIG. 18 is a graph showing the short-circuit rate between the tab and the coated wire with respect to the temperature cycle in the present invention.

The semiconductor device of this embodiment is an example of a resin-encapsulated semiconductor device 1, and its semiconductor chip 2 can be configured as a semiconductor integrated circuit element such as a memory, a gate array, a microprocessor, and a MOS logic.

The semiconductor chip 2 includes a substrate 2A made of silicon (Si) and a passivation film 2B on the top.
And an external terminal (bonding pad) 2C exposed from the opening of the passivation film 2B. The semiconductor chip 2 is joined to the tab 3A of the lead 3 by a joining material 4 such as a silver (Ag) paste.

On the other hand, the external terminals 2C of the semiconductor chip 2 are electrically connected to the inner leads 3B of the leads 3 by conductive wires. In this embodiment, the covering wires 5 are used as the conductive wires. This coated wire 5 is a metal wire 5A
And a structure in which an insulating coating film 5B is applied to the surface of the substrate.

The material of the metal wire 5A of the covered wire 5 is, for example, gold (A
u), copper (Cu) or aluminum (Al) can be used.

The coating film 5B of the coating wire 5 is obtained by reacting a polyol component with an isocyanate, as described above and in detail later, and is made of a heat-resistant polyurethane having a molecular skeleton containing a structural unit derived from terephthalic acid. It becomes.

The coated wire 5 of the present embodiment has its first (first =
1st) The bonding side, that is, the connection side between the external terminal 2C of the semiconductor chip 2 and one end of the covering wire 5 is a metal ball.
While being conductively connected by ball bonding by the formation of 5A _1, second (first 2 = 2nd) bonding side, i.e. the connection is thermocompression and ultrasonic vibration to the other end of the inner lead 3B and the coated wire 5 of the lead 3 the so-called thermo-sonic bonding using are conductively connected as second bonding portion 5A ₂ without prior removal of the coating film 5B.

The semiconductor chip 2 thus pellet-bonded and wire-bonded and the tab of the lead 3 are formed.
3A, the inner lead 3B, and the covering wire 5 are sealed with a resin material 6 such as an epoxy resin, for example.
Only the outer leads 3C protrude outside the resin material 6.

Next, the configuration and operation of the wire bonding apparatus for bonding the covered wire 5 in the present embodiment will be described mainly with reference to FIGS.

The wire bonding apparatus is configured as a so-called ball bonding apparatus. The ball bonding apparatus is configured to supply the covering wire 5 wound around the spool 11 to the bonding section 12 as shown in FIG. Have been.

That is, the supply of the covering wire 5 from the spool 11 to the bonding section 12 is performed through the tensioner 13, the wire guide member 14, the wire clamper 15, and the bonding tool (capillary) 16.

The resin-sealed semiconductor device 1 before resin sealing, which is configured as shown in FIG. 3 and FIG. Then, as shown in FIG. 3, the resin-encapsulated semiconductor device 1 before resin encapsulation is mounted on a semiconductor device support base (semiconductor device mounting table) 17 of a bonding apparatus.
It is supported by.

An external terminal 2C of the semiconductor chip 2 has a coating wire 5
Coating film 5B at one end is connected to the metal balls 5A ₁ formed by the exposed metal lines 5A been removed. Metal ball 5A ₁
Has a diameter that is, for example, about two to three times larger than the diameter of the metal wire 5A. The inner lead 3B of the lead 3 is connected to a metal wire 5A on the other end of the covered wire 5 that is exposed by breaking the covering film 5B on the other end of the covered wire 5 in the connection portion. That is, the other end side of the covering wire 5 is configured so that substantially only the covering film 5B at the connection portion with the lead 3 is removed, and the other covering film 5B remains. A coating film on the other end side of the coating wire 5
As will be described later, the 5B can be destroyed by ultrasonic vibration, appropriate pressurization, and appropriate heating (energy) provided by the bonding tool 16.

As described above, in the resin-encapsulated semiconductor device 1 using the covering wire 5, the metal terminal 5 </ b> A formed on the one end side of the covering wire 5 is attached to the external terminal 2 </ b> C of the semiconductor chip 2.
5A ₁ is connected to the inner lead 3B of the lead 3, and the metal wire at the other end of the coated wire 5 in which the coating film 5B at the contact portion is broken.
5A, the size of the metal ball 5A ₁ is large, so that the external terminal 2C of the semiconductor chip 2 and the covering wire 5A are connected.
The contact area with the metal wire 5A can be increased, the bondability between the two can be improved, and the other end of the covered wire 5 other than the portion connected to the inner lead portion 3B of the lead 3 is covered with the covering film 5B. And short-circuiting between the other end of the covered wire 5 and the other end of the adjacent covered wire 5 can be reduced. It is possible to increase the number of terminals (so-called, more pins).

Feed direction of the distal end portion of the bonding tool 16 and the insulated wire 5 (metal balls 5A ₁ forming portion), as shown in the FIGS. 3 and 4, during the formation of metal balls 5A _1, covering the covering member 18A It is configured to be. The covering member 18A is configured to rotate in the direction of arrow A shown in FIG. That is, the covering member 18A
, Upon formation of the metal balls 5A _1, and insert the bonding tool 16 from the tool insertion opening 18B by the rotation operation direction of the arrow A, and is configured so as to cover it.

This covering member 18A is shown in FIG. 5 (partial sectional view showing a specific configuration, corresponding to a section taken along the line VV in FIG. 6), FIG. 6 (from the direction of arrow VI in FIG. 5). FIG. 7 (a cross-sectional view taken along the line VII-VII in FIG. 6).
It is configured as shown in FIG. As will be described later, the coating member 18A is a coating film 5B that melts when the metal ball 5A ₁ is formed.
It is configured such that the coating film 5B does not scatter to the bonding portion 12 by blowing away. When the metal wire 5A of the coated wire 5 is formed of an easily oxidizable material such as Cu or Al, the coating member 18A is configured to easily hold the coating gas atmosphere for preventing oxidation (shield gas atmosphere). I have. Covering member
18A is formed of, for example, stainless steel. Further, the covering member 18A is a state of formation of the metal balls 5A _1, etc. coated wire 5 so the operator can confirm, it may be formed of a glass material having transparency.

As shown in FIGS. 3, 4 and 5, an electric torch (arc electrode) 18D is provided on the bottom of the covering member 18A.
Is provided. The electric torch 18D is, as shown in FIG. 8 (a schematic configuration diagram illustrating the principle of forming a metal ball),
Close to the metal wire 5A on the tip side on the supply side of the coated wire 5,
It is configured to generate an arc Ac to form a metal ball 5A ₁ in between them. The electric torch 18D is formed of, for example, tungsten (W) that can withstand high temperatures.

Electric torch 18D is a suction device 1 made of conductive material
It is connected to the arc generator 20 via a suction pipe 18E to the pipe 9. The suction tube 18E is made of, for example, stainless steel, and fixes the electric torch 18D with an adhesive metal layer such as an Ag-Cu brazing material interposed therebetween. The suction tube 18E is fixed to the covering member 18A with the holding member 18F interposed therebetween.
That is, the electric torch 18D, the suction tube 18E and the covering member 18A
And are integrally formed.

The electric torch 18D is proximate the distal end of the supply side of the coated wire 5 when forming the metal balls 5A ₁ as described above,
It is configured to be movable in the direction of arrow A shown in FIG. 4 so that it can be separated from the supply path of the covering wire 5 during the bonding step. The moving device for moving the electric torch 18D mainly includes a support member 18G for supporting the electric torch 18D with the suction tube 18E and the insulating member 18H interposed therebetween, a crankshaft 18I for rotating the support member 18G in the direction of arrow A, A drive source 18K for rotating the crankshaft 18I is provided. The rotation of the crankshaft 18I is performed by the movement of the shaft 18J of the drive source 18K in the direction of the arrow B connected to the crank portion. Drive source 18K is formed of, for example, an electromagnetic solenoid. Although not shown, the crankshaft 18I is rotatably supported by the bonding apparatus main body. Note that the movement of the electric torch 18D and the movement of the covering member 18A are substantially the same because they are integrally formed.

As shown in FIG. 4, the arc generator 20 mainly includes a capacitor C ₁ , a storage capacitor C ₂ , a thyristor D for generating an arc activated by a trigger, and a resistor R.
The DC power supplies D and C are configured to supply a negative polarity voltage of, for example, about -1000 to -3000 [V]. DC power supplies D and C are connected to an electric torch 18D via a thyristor D, a resistor R and the like. The reference potential GND is, for example, a ground potential (= 0 [V]). V is a voltmeter and A is an ammeter.

As will be described in detail later, the metal wire 5A of the covering wire 5 is a spool.
The end wound around 11 is connected to the reference potential GND. As a result, when forming a metal ball 5A ₁ to the distal end portion of the covered wire 5 with electric torch 18D, FIG. 3, as shown in FIG. 4 and FIG. 8, an electric torch 18D negative potential (-), the coating The metal wire 5A at the distal end in the supply direction of the wire 5 can be set to a positive potential (+).

Thus, the arc Ac is generated between the metal wire 5A at the tip of the covered wire 5 and the arc electrode 18D, and the covered wire 5
In bonding apparatus for forming a metal ball 5A ₁ at the tip of the metal wire 5A of the covered wire 5 is connected to a positive potential (+), an electric torch 18D negative potential (-) by connecting to the coated wire The position of the arc Ac generated between the metal wire 5A and the electric torch 18D can be stabilized as compared with the case of the opposite polarity, so that the arc Ac is located behind the metal wire 5A of the coated wire 5. Crawling up to the end side can be reduced. The reduction of the crawling of the arc Ac reduces the melting of the coating film 5B of the coating wire 5,
The generation of spheres of the insulating coating film can be prevented.

Note that the present invention connects the metal wire 5A of the coated wire 5 to a voltage higher or lower than the reference potential GND so that the metal wire 5A of the coated wire 5 has a positive potential with respect to the electric torch 18D. You may.

The spool 11 around which the coating wire 5 is wound,
It is configured as shown in FIGS. 4 and 9 (an exploded perspective view of a main part). The spool 11 is formed by, for example, performing alumite treatment on a surface of a cylindrical aluminum metal. The alumite treatment is performed to improve mechanical strength and prevent scratches. As described above, the spool 11 has an insulating property because it is anodized.

The spool 11 is attached to a spool holder 21,
The spool holder 21 is attached to the bonding apparatus main body 10 by a rotation shaft 21A.

The spool holder 21 is made of, for example, stainless steel so that at least a part thereof has conductivity.

The spool 11 is provided with a connection terminal 11A as shown in FIGS. 9 and 11 (an enlarged perspective view of a main part). The connection terminal 11A is provided in a dotted shape on a side surface portion (flange) of the spool 11 that comes into contact with a conductive portion of the spool holder 21.

As shown in FIG. 10, the connection terminal 11A is configured such that a conductor 11Ab is provided on an insulator 11Aa, and a connection metal part 11Ac is provided on the conductor 11Ab. The insulator 11Aa is electrically separated from the conductor 11Ab and the spool 11 reliably, and furthermore, is made of, for example, a polyimide resin so as to have an appropriate elasticity so that the connection metal portion 11Ac can be reliably brought into contact with the spool holder 21. Form. The conductor 11Ab includes a connection metal part 11Ac for connecting the metal wire 5A of the covered wire 5 and a spool holder 21A.
It is formed of, for example, a Cu foil so that the connection metal portion 11Ac that comes into contact with the contact can be reliably connected. The connection metal part 11Ac is formed of a conductive paste, solder, or the like.

The connection terminal 11A passes through a notch formed in the side surface (flange) of the spool 11, and the metal wire 5A at the end of the sheath wire 5 opposite to the side supplied to the bonding portion 12, ie, the sheath wire 5A. Is configured to connect the metal wire 5A at the start end of the winding. This metal wire 5A is a metal part for connection.
Connected to the connection terminal 11A by 11Ac. Insulated wire 5
The coating film 5B on the surface of the metal wire 5A at the beginning of winding is heated or chemically removed. The connection terminal 11A, that is, the metal wire 5A of the covering wire 5 is connected to the reference potential GND through the spool holder 21, its rotating shaft 21A and the bonding apparatus main body 10. The reference potential GND is the arc generator 20.
Is the same as the reference potential GND.

Thus, by providing the spool 11 with the connection terminal 11A for connecting to the reference potential GND, and connecting the metal wire 5A at the winding start end of the covering wire 5 to this connection terminal,
Since the connection can be made to the reference potential GND through the spool holder 21 or the like, the metal wire 5A of the covering wire 5 can be reliably connected to the reference potential GND.

Further, the by metal wire 5A of coated wire 5 is connected to the reference potential GND, and during the formation of metal balls 5A _1, sufficient potential difference between the electric torch 18D and the metal wire 5A of coated wire 5 on the supply side reserved, since arcing Ac can be improved, it is possible to reliably form the metal ball 5A _1.

As shown in FIGS. 3 and 4, the bonding tool 16 is supported by a bonding head (digital bonding head) 22 via a bonding arm 16A. Although not shown, the bonding arm 16A has a built-in ultrasonic vibration device, and is configured to ultrasonically vibrate the bonding tool 16. The bonding head 22 is supported by a base 24 with an XY table 23 interposed. The bonding head 22
A moving device capable of moving the bonding arm 16A in the vertical direction (the direction of arrow C) is provided so that the bonding tool 16 can be moved toward and away from the bonding section 12. The moving device mainly includes a guide member 22A, an arm moving member
22B, a female screw member 22C, a male screw member 22D, and a motor 22E. The guide member 22A is configured to move the arm moving member 22B in the direction of arrow C. The motor 22E is configured to rotate the male screw member 22D, move the female screw member 22C fitted with the male screw member 22D in the direction of arrow C by this rotation, and move the arm moving member 22B in the direction of arrow C by this movement. Have been.

Bonding arm 1 supported by arm moving member 22B
6A is configured to rotate around a rotation shaft 22F. The rotation of the bonding arm 16A about the rotation axis 22F is controlled by the elastic member 22G. This elastic member 22G
The rotation control is configured to prevent the bonding unit 12 from being pressed more than necessary when the bonding tool 16 comes into contact with the bonding unit 12, and to prevent damage or destruction of the bonding unit 12. I have.

The wire clamper 15 can hold the covering wire 5 and is configured to control the supply of the covering wire 5. The wire clamper 15 is provided on the bonding arm 16A with the clamper arm 15A interposed.

The wire guide member 14 is configured to guide the covered wire 5 supplied from the spool 11 to the bonding section 12. The wire guide member 14 is provided on the clamper arm 15A.

As shown in FIGS. 3 and 8, in the vicinity of the leading end of the covering wire 5 in the supply direction and in the vicinity of the supply path of the covering wire 5 between the bonding tool 16 and the bonding portion 12, as shown in FIGS. A fluid spray nozzle 18C of the fluid spray device 25 is provided. Fluid spray nozzles 18C, when forming the metal balls 5A ₁ with metal wire 5A of the distal end portion of the supply direction of coated wire 5, fluid from the fluid spray device 25 to the forming portion (metal lines 5A and coating film 5B) It is configured to spray Gs. Fluid Gs blown out from fluid spray nozzle 18C
As shown in FIG. 8, when forming a metal ball 5A ₁ with metal wire 5A of the distal end portion of the covered wire 5, blows melt increases coating film 5A by the heat generated by the arc Ac of (5Ba) It is configured as follows.

The fluid spray nozzle 18C may basically spray the fluid Gs on the tip portion of the bonding tool 16, that is, the tip portion of the coating wire 5 as described above. In the present embodiment, the fluid spray nozzle 18C is provided on the coating member 18A. ing. As shown in FIG. 4 to FIG. 7, the fluid spray nozzle 18C is provided with a fluid from the rear end side to the front end side of the coated wire 5 to reduce the melting of the coating film 5B. It is configured to spray Gs. The fluid spray nozzle 18C
Is preferably not attached to the bonding tool 16. When the fluid spray nozzle 18C is attached to the bonding tool 16, the weight of the bonding tool 16 increases,
Since the load of the ultrasonic vibration increases, the bondability of the connection portion decreases.

As the fluid Gs, a gas such as N ₂ , H ₂ , He, Ar, or air is used. As shown in FIG. 8, a fluid spraying device (fluid source) 25 supplies a cooling device 25 A, a flow meter 25 B, The fluid is supplied to the fluid spray nozzle 18C via the pipe 25C.

The cooling device 25A is configured to actively cool the fluid Gs below normal temperature. The cooling device 25A is configured by, for example, an electronic cooling device using the Peltier effect. The fluid transfer pipe 25C is shown in a simplified form in FIG. 8, but is configured to cover at least the space between the cooling device 25A and the supply port of the fluid spray nozzle 18C with a heat insulating material 25D. That is, the heat insulating material 25D is the fluid cooled by the cooling device 25A.
It is configured not to change the temperature of Gs during the movement of the fluid transport pipe 25C (to increase the cooling efficiency).

Further, in the vicinity of the leading end of the coating wire 5 in the supply direction, and at a position facing the fluid spray nozzle 18C around the melted portion of the coating film 5B of the coating wire 5,
A suction tube 18E connected to the suction device 19 is provided. As described above, the suction pipe 18E is also used as a conductor for connecting the electric torch 18D and the arc generator 20, but mainly the melting of the coated wire 5 blown off by the fluid spray nozzle 18C. It is configured to suck the coated film 5Ba. The coating film 5Ba sucked by the suction tube 18E is
The suction is performed by the suction device 19.

Further, in the present embodiment, only the inner lead 3B of the lead 3 is higher than the other parts in order to more securely bond (second bond) the other end of the covered wire 5 to the inner lead 3B of the lead 3. The ceramic heater 26 for locally heating to a temperature is shown in FIGS.
It is provided in a square ring shape as shown in the figure. Reference numeral 26A denotes a power supply line to the rectangular ring-shaped heater 26 for local heating.

Next, the wire bonding method of this embodiment will be briefly described.

First, as shown in FIG. 3, FIG. 4, FIG. 5, and FIG. 8, the bonding tool 16 and the leading end portion of the coating wire 5 protruding toward the pressing surface thereof in the supply direction are coated with a coating member 18A.
Cover with. This coating is performed by moving the coating member 18A in the direction of arrow A by the moving device operated by the driving source 18K. Further, by performing the coating with the coating member 18A, the electric torch 18D, the fluid spray nozzle
Each of the 18Cs can be placed near the distal end of the coated wire 5.

Next, as shown in FIG. 8, an arc A is provided between the metal wire 5A at the end of the coating wire 5 in the supply direction and the electric torch 18D.
c is generated to form a metal ball 5A ₁ by the metal wire 5A. By arc Ac heat to form a metal ball 5A _1, the insulating coating film 5B of the supply direction of the distal end portion of the covered wire 5
Melts up. That is, the coating film 5B at the tip in the supply direction of the coating wire 5 is removed, and the metal wire 5A is exposed.

Formation of metal balls 5A ₁ is carried out in the shortest possible time.
Short, yet high energy to form a metal ball 5A ₁ in (current, each of the higher voltage region), the covered wire 5
Of the coating film 5B is reduced. in this way,
Short time formation of the metal balls 5A _1, be carried out at high energy, as described above, to stabilize arcing Ac, that is, the electric torch D negative potential (-) to the metal wire coated wire 5
This can be achieved by setting 5A to a positive potential (+).

When forming the metal ball 5A _1, sprayed fluid Gs from the fluid spray device 25 in the fluid spray nozzle 18C which position is set with the covering member 18A to dissolve up the coating film 5B covering the wire 5, 8 As shown in the figure, the coating film 5B is blown off. The blown coating film 5Ba is sucked by the suction device 19 through the suction pipe 18E, and is removed out of the system.

The fluid Gs from the fluid spray nozzle 18C is cooled to, for example, about 0 to -10 [° C.] by the cooling device 25A shown in FIG. Fluid Gs from fluid spray nozzle 18C
The lower the temperature is, the smaller the melting amount of the coating film 5B of the coating wire 5 is. That is, the fluid Gs cooled by the cooling device 25A
Since the metal wire 5A, the coating film 5B, the bonding tool 16 and the like of the coating wire 5 can be actively cooled,
Melts the coating film 5B only on the part where Ac is generated, and coats the coating film on other parts.
5B is not melted, and as a result, the amount of melting of the coating film 5B can be reduced.

Next, the covering member 18A and the electric torch 1
8D, and each of the fluid spray nozzles 18C is moved in the direction of arrow A (the direction opposite to the above).

Next, a metal ball 5A ₁ formed on the pressing surface of the bonding tool 16 at the tip end in the supply direction of the covering wire 5 is formed.
Attraction.

Next, in this state, the bonding tool 16 is moved closer to the bonding portion 12, and as shown by the broken line in FIG. 2, the metal ball 5A ₁ formed at the tip of the covering wire 5 in the supply direction. To the external terminal 2C of the semiconductor chip 2 (fast bonding: 1s
t). This metal ball 5A ₁ connection is a bonding tool
16 ultrasonic vibrations and / or thermocompression bonding (one or the other).

Next, as shown in FIG. 2, the metal wire 5A at the rear end of the covered wire 5 is connected to the inner lead 3B of the lead 3 by a bonding tool 16 (second bonding: 2n).
d). The connection on the rear end side of the covered wire 5 is performed by ultrasonic vibration and thermocompression bonding of the bonding tool 16 (the former may be used alone).
Do with. Thus, the rear end of the insulated wire 5 and the inner leads 3B at second bonding portion 5A _2, are firmly wedge bonding.

The connection at the rear end side of the coated wire 5 is such that the coated wire 5 at the connection portion is coated in advance with the coating film 5B, but the coating film 5B only at the connection portion is formed by ultrasonic vibration of the bonding tool 16. It is destroyed, and the metal wire 5A is exposed. Although there is a slight change depending on the energy of the ultrasonic vibration of the bonding tool 16 and the thermocompression force, the coating film 5B of the coating wire 5 is preferably, for example, about 0.2 to 3 [μm] thick. When the thickness of the coating film 5B of the coating wire 5 is too small, the withstand voltage as the insulating coating film is small. If the thickness of the coating film 5B of the coating wire 5 is too large, the coating film 5B is less likely to be broken by the ultrasonic vibration of the bonding tool 16, and the coating film 5B has a predetermined value. If it exceeds, the coating film 5B will not be destroyed, resulting in poor connection between the metal wire 5A of the coating wire 5 and the inner lead 3B of the lead 3.

In this embodiment, when the other end of the covered wire 5 is bonded (second bonding), only the inner lead 3B of the lead 3 is locally heated by the heater 26 to a temperature which is particularly higher than the other portions. Since the heating / decomposition of the covering film 5B is further promoted, the bondability of the second bonding can be improved, and strong wire bonding can be performed.

Thereafter, the bonding tool 16 is separated (at this time, the covering wire 5 is cut), thereby completing one bonding step of the covering wire 5 as shown in FIG.

Thus, the metal ball 5A ₁
In the bonding technique for forming a wire, fluid Gs is applied to the tip of the covered wire 5 near the tip of the covered wire 5.
By providing a fluid spray nozzle 18C (a part of the fluid spray device 25) for spraying the coating wire 5B, the coating film 5B that melts the coating wire 5 can be blown off. Can be prevented from being formed. As a result, the coated wire 5 is prevented from being caught by the bonding tool 16 due to the sphere of the insulating coating film 5B, and the coated wire 5 can be drawn to the pressing surface of the bonding tool 16, so that ball bonding is performed. And bonding defects can be prevented.

Further, a bonding technique to form a metal ball 5A ₁ to the distal end portion of the covered wire 5, wherein the fluid spray nozzle 18
C (a part of the fluid spraying device 25) is provided, and a suction pipe for sucking a coating film 5B of the coated wire 5 blown off by spraying the fluid Gs from the fluid spray nozzle 18C near the tip of the coated wire 5. By providing 18E (suction device 19)
Blow off the coating film 5B, which melts the coating wire 5,
The sphere of the coating film 5B is prevented from being formed on the coating wire 5 and the bonding failure can be prevented as described above, and the blown coating film 5Ba is not scattered to the bonding portion 12, so that the scatter is prevented. It is possible to prevent bonding failure caused by the applied coating film 5Ba. The bonding failure caused by the scattered coating film 5Ba is, for example, that the coating film 5Ba is scattered between the external terminal 2C of the semiconductor chip 2 or the inner lead 3B of the lead 3 and the metal wire 5A of the coating wire 5. However, this is the case where conduction failure occurs between the two.

Further, a bonding technique to form a metal ball 5A ₁ to the distal end portion of the covered wire 5, wherein the fluid spray nozzle 18
By providing C (fluid spray device 25) and cooling device 25A for cooling the fluid Gs of the fluid spray nozzle 18C, melting of the insulating coating film 5B of the coated wire 5 is significantly reduced, and Even in this case, since the coating film 5B can be blown off, it is possible to prevent the sphere of the coating film 5B from being formed on the coating wire 5 and prevent the bonding failure as described above.

In the bonding technique using the covered wire 5, a metal ball 5A
_Then , the metal ball 5A ₁ is connected to the external terminal 2C of the semiconductor chip 2, the rear end side of the covering wire 5 in the supply direction is brought into contact with the inner lead 3B of the lead 3, and the contact portion is covered. A covering film for removing the covering film 5B on the rear end side of the covering wire 5 by breaking the covering film 5B and connecting the metal wire 5A on the other end side of the covering wire 5 to the inner lead 3B of the lead 3. Since the coating film 5B can be removed without using a removing torch, it is possible to reduce the coating film removing torch, its moving device, control device, and the like. As a result, the structure of the bonding apparatus can be simplified.

In particular, in the semiconductor device 1 of the present embodiment, a heat-resistant polyurethane containing a structural unit derived from terephthalic acid in the molecular skeleton is used as the insulating coating film 5B of the coating wire 5 by reacting a polyol component with an isocyanate. As a result, it is possible to reliably prevent a tab short, a chip short, or a short between wires due to film destruction caused by thermal differentiation of the coating film 5B.

That is, after bonding the covering wire 5 as described above, a resin molding operation is performed with the resin material 6 to manufacture the resin-encapsulated semiconductor device 1. For example, as shown in FIG. When the distance between the external terminal 2C of the chip 2 and the bonding portion of the inner lead 3B of the lead 3 is long, as shown in FIG.
A so-called chip touch state in which the silicon wire of the semiconductor chip 2 contacts with the so-called chip touch state, or a so-called tab touch state in which the covering wire 5 and the tab 3A contact each other as shown in FIG.
Further, a so-called wire-to-wire touch state where the coated wires 5 come into contact with each other may occur. Such a wire touch phenomenon tends to occur particularly when the wire length becomes 2.5 mm or more, or when the size of the tab 3A is larger than the size of the semiconductor chip 2.

When such a wire touch phenomenon occurs, for example, as shown in FIG. 14, the coating film 5B of the coating wire 5 is broken by thermal deterioration caused by heat generation from the semiconductor chip 2, and the metal wire 5A is 2 is in direct contact with the semiconductor chip 2
In some cases, a short-circuit between the wires may occur, or as shown in FIG. 16, a short-circuit between the tabs 3A may occur, and a short-circuit between the wires may occur.

However, in the semiconductor device 1 of the present embodiment, as described above, since the coating film 5B of the coating wire 5 is made of a special heat-resistant polyurethane, it is temporarily assumed that the chip touch, the tab touch or the wire Even if a touch state occurs, it is possible to reliably prevent a short circuit from occurring.

In order to confirm the effect of preventing short-circuit failure according to the present invention, the results of an experiment performed by the present inventors on a semiconductor device after resin sealing will be described below as Experimental Example 1.
Parts in the experimental examples indicate parts by weight.

Experimental Example 1 First, raw materials as shown in Table 1 below were blended in a ratio as shown in the table, and this was put into a 500 cc flask.
A thermometer and a steam condenser were attached and reacted to obtain three types of terephthalic acid-based polyols P-1, P-2 and P-3. Table 1 also shows the ratio of terephthalic acid and ethylene glycol and the reaction time at this time. The end point of the above synthesis reaction was determined based on theoretical reaction water and an acid value of 5 or less. In this case, a reduced pressure reaction was performed as needed.

Using the three types of terephthalic acid-based polyols P-1, P-2, P-3 obtained as described above and commercially available polyols, these polyol components and isocyanate components are shown in Table 2 below. A coating composition was prepared by blending at such a ratio. Then, the coating composition thus obtained was diluted to a concentration of 10% using a solvent, and 2 μm
Apply at least 175 ° C for 21 minutes, then 170 ° C
After 2 hours, an insulating coating made of heat-resistant polyurethane was formed, and a wire was formed. The composition and coating film properties in this case are shown in Table 2 below.

Next, using the heat-resistant polyurethane-coated wire obtained as described above, the semiconductor chip wire-bonded as described above is molded with a resin material, and FIG. 13 (chip touch state) and FIG. 15 (tab touch state). A semiconductor device corresponding to the touch state shown in Fig. 1 was manufactured, a temperature cycle test of MIL-883B was performed, and a short-circuit rate with a semiconductor device using a commercially available polyurethane-coated wire was compared to evaluate the improvement of the present invention. did.

The results of this comparative experiment were as shown in FIG. 17 and FIG. That is, FIG. 17 shows the short-circuit rate between the semiconductor chip and the coated wire in the chip touch state as shown in FIG. 13. As is clear from FIG. 17, the semiconductor using the heat-resistant polyurethane-coated wire of the present invention was used. In the device, a remarkable short-circuit rate, that is, a chip short-circuit preventing effect was confirmed as compared with a semiconductor device using a commercially available polyurethane-coated wire.

FIG. 18 shows the short-circuit rate between the tab and the coated wire in the tab chip state as shown in FIG. 15, but also in this case, the semiconductor device using the heat-resistant polyurethane-coated wire of the present invention has a remarkable short-circuit. Rate, that is, a tab short prevention effect was obtained.

Next, the present inventors compared the heat-resistant polyurethane-coated wire according to the present invention and a commercially available polyurethane-coated wire in a wire state before resin sealing under the test conditions described below,
The wear strength and the deterioration rate of the coating film were evaluated. The results of these experiments and other various experiments are described below in Experimental Examples 2 to 5.
19 to 25 will be described.

Experimental Example 2 Experimental conditions were represented by a model diagram shown in FIG. That is, a fixed load (1 g) is hung on the lower end of the insulated wire 5 whose outer surface is coated with an insulating coating film (heat-resistant polyurethane of the present invention or commercially available polyurethane) 5B to make a vertically suspended state, The tab 3A of the lead frame is brought into contact with the coated wire 5 at the edge thereof at a contact angle α = 45 degrees, and pressed against the coated wire 5 with a load W ₁ (0.65 g) in the horizontal direction from the opposite side of the tab edge contact portion. By applying force and oscillating the tab 3A vertically by 20 μm,
The wear of the coating film 5B was evaluated.

Here, the amplitude (vibration) frequency Nf until the coating film 5B wears and breaks is defined as a wear strength and evaluated.

In addition, the heat resistance of the coating film 5B is high temperature storage (150-200 ° C,
(0 to 1000 hours).

As a result, it has been found that, in the case of polyurethane, thermal degradation can be greatly suppressed by imidizing the polyurethane, and the temperature cycle life T∞ can be significantly improved.

 Hereinafter, these experimental results will be specifically described.

First, FIGS. 20 and 21 show the thermal deterioration of the wear strength of the coating film 5B at 150 ° C. and 175 ° C., respectively (reduction of the number of coating film breakage after 100 hours). As is apparent from these figures, in the case of the coating film using the heat-resistant polyurethane of the present invention, the wear strength Nf even after the high-temperature leaving time has elapsed.
Was found to be small, and the deterioration of the coating film was very small. In particular, it was found that the fact that the rate of deterioration of the coating film 5B in reducing the number of times the coating film was destroyed after 150 to 175 ° C for 100 hours (Hrs) was within 20% was an extremely advantageous characteristic for the coated wire.

Experimental Example 3 Next, FIG. 22 shows the experimental results of the relationship between the temperature (horizontal axis) and the deterioration rate, that is, the deterioration rate [ΔNf / 100Hrs] (= N ₀ −N ₁₀₀ / 100Hrs) (vertical axis). is there. Also in this figure,
It is understood that the degradation rate of the heat-resistant polyurethane-coated wire of the present invention is much smaller than that of the commercially available polyurethane.

Experimental Example 4 Next, FIG. 23 shows the imidization ratio (horizontal axis) of the coating film, the degradation rate, that is, the deterioration rate (vertical axis on the left), and the peel strength of the second (2nd) bonding of the coated wire (vertical axis on the right). It is an experimental result showing the relationship with.

The peel strength of the 2nd bonding was determined by the inventors of the present invention using a heat-resistant polyurethane-coated wire having a diameter of φ = 25 μm and bonding the inner film 3B to the inner lead 3B without previously peeling the coating film 5B as shown in FIG. This is the result of performing.

As is clear from FIG. 23, the imidization ratio of the coating film is about
1/3 is preferable for both the deterioration rate (deterioration rate) and the peel strength.

In particular, in the case of the heat-resistant polyurethane-coated wire of the present invention,
Since the peel strength of the 2nd bonding part was large, the reliability of bonding was high and an extremely advantageous result was obtained.

Experimental Example 5 FIG. 24 shows the experimental results on the temperature cycle amplitude (−55 to 150 ° C.) and the temperature cycle life of the coated wire. As is clear from the figure, the service life T の of the coating film made of a commercially available polyurethane is about 400, while that of the heat-resistant polyurethane of the present invention is greatly improved to 4000 or more.

Experimental Example 6 FIG. 25 is a diagram showing the results of an experiment on the effect of the presence or absence of a coloring agent on the coating film of a coated wire on the deterioration rate (deterioration rate).

According to the knowledge of the present inventors, when performing bonding using the covered wire 5, for example, when forming a metal ball, since the thickness of the covering film 5B is very thin, it is determined whether or not the coating film 5B melts or peels. It is very difficult to confirm, and at least it is impossible with the naked eye. Therefore,
The present inventors have found that if a coloring agent such as oil scarlet is added to the coating film 5B, the dissolution or peeling thereof can be visually confirmed (for example, by using an electron microscope), and is extremely useful. .

However, if the amount of the coloring agent added is too large, the deterioration rate (deterioration rate) of the coating film increases, and the present inventors conducted various experiments on the appropriate amount, and as a result, Is shown in FIG.

As is clear from the experimental results shown in FIG. 25, when the amount of the colorant added is too large, the deterioration rate (deterioration rate) of the coating film increases, while when the amount is too small, the above-mentioned results are obtained. The merit of adding such a coloring agent is lost. So, in light of these two conflicting requirements,
As a result of extensive studies by the present inventors, the amount of the coloring agent (in this example, oil scarlet) was 2.0% by weight or less,
In particular, it became clear that 0.5% by weight to 2.0% by weight was optimal. By adding a colorant to the coating film in this range, the advantage that the coating film can be visually confirmed as melting or peeling from the coating wire while preventing the characteristics of the coating film from being impaired is obtained. Can be

The present inventors have obtained the following findings through Experimental Example 1, further Experimental Examples 2 to 6, and various other experiments, studies, studies, and confirmations.

That is, as described above, the use of the heat-resistant polyurethane having the above composition of the present invention as the coating film of the coated wire is extremely useful for the thermal deterioration of the coating film, the bonding property, and the improvement of the peeling strength of the bonding.

In addition to this, as is clear from, for example, Experimental Example 2 and the like, the thermal degradation (degradation rate) of the coating film, that is, the abrasion test under the experimental conditions shown in FIG. It is extremely important to use a material that can reduce the degradation rate within 20% in reducing the number of times the coating film is destroyed after 100 hours at 150 ° C. to 175 ° C. as a constituent material of the coating film.

In addition, as a characteristic to be provided as a coating film, it is also very important that the coated wire does not cause a problem in bonding property when the coated wire is put to practical use in a wire bonding operation. The present inventors have conducted intensive studies on this point. As a result, it is important that the coating film is made of a material that exhibits non-carbonization, for example, when forming metal balls in ball bonding or when removing the coating film by heating. It has been found.

The reason is as follows. In other words, the coating film melts immediately above the metal ball when forming the metal ball or removing the coating film by heating, but if the coating film is carbonized, the coating film is decomposed by the heating temperature at that time, for example, a high temperature of 1060 ° C. Instead, it is carbonized. As a result, the carbonized coating film adheres and remains on the metal ball just above the metal ball so as to wrap the metal wire.When bonding with a bonding tool, the carbonized coating film is supplied by the coated wire passing through the capillary. This makes it difficult or impossible for the coated wire to pass through the capillary. On the other hand, if the deposited carbonized coating film falls on the integrated circuit forming surface of the semiconductor chip for some reason, the carbide has conductivity, and the dropped object causes an electrical short-circuit failure of the integrated circuit. It is. In addition, it has been found that the coated wire to which the carbide has adhered causes a bonding failure, for example, also at the time of the second bonding to the inner lead.

Considering such facts comprehensively, as the coating film of the coated wire, the deterioration rate under the above-mentioned predetermined conditions, ie, 150 ° C. to 175 ° C., in reducing the number of times of coating film destruction after 100 hours It is extremely important that the deterioration rate is within 20% and that these two conditions are non-carbonizable at the time of forming the metal ball or at the time of removing the coating film by heating. It has been confirmed by the inventors that very satisfactory results can be obtained as a coated wire.

According to the study results of the present inventors, the heat-resistant polyurethane having the above-described composition is, of course, one that satisfies these two requirements. However, the material that satisfies these two requirements is only the heat-resistant polyurethane having the above-described composition. The material is not limited, and a heat-resistant polyurethane having another composition, or a material other than the heat-resistant polyurethane, can be used as the material of the preferable coating film.

In this regard, among polyurethanes, commercially available polyurethanes and formals satisfy the requirement of non-carbonization, but the deterioration rate is more than 20%, so that they cannot be said to be optimal as coating films.

On the other hand, polyimide, polyamide, nylon, polyester, polyamide imide, polyester imide, etc. exhibit carbonization when forming metal balls or when removing the coating film by heating, and therefore have drawbacks when used as a coating film for a coating wire. It turned out to be less than optimal.

Next, the present invention will be further described with reference to FIGS. 26 to 30 showing other various embodiments of the wire bonding method which can be used in the present invention.

26 In II of Example-1 of Figure, as an example of another wire bonding method included in the present invention, first the coated wire 5 (1st) bonding side ball bonding also by metal balls 5A ₁ as in Example 1 is a method, as the second (2nd) bonding side shown as second bonding portion 5A _22, prior to the 2nd bonding to remove the pre-coated film 5B, performs 2nd bonding with thermocompression and / or ultrasonic vibration method Things.

Next, in III of Example-1 of FIG. 27, second bonding portion 5A ₂ is coated in film and I of Example-1 5
In addition to bonding without removing B, the first bonding side is not ball bonding with metal balls, but is first bonded by thermocompression bonding and / or ultrasonic vibration without removing the coating film 5B in advance. and to form a first bonding portion 5A _11.

Therefore, in the present embodiment, the same bonding method is used for both the first and second bonding.

Furthermore, IV of example-1 of FIG. 28 is first bonding portion 5A ₁₁ is the same as III of Example-1, also the second bonding portion 5A ₂₂ and II of Example-1,
The coating film 5B is removed in advance and bonded.

29, the first bonding portion 5A ₁₂ is a bonding method in which the coating film 5B is removed in advance, and the second bonding portion 5A ₂ is the same as I and III of the first embodiment. The bonding is performed without removing the coating film 5B.

Further, in the VI of the embodiment 1 of FIG. 30, the first bonding portion 5A ₁₂ and the second bonding portion
Metal lines 5A the state in which the previously removed covering film 5B of 5A ₂₂
Is an example of bonding by a non-ball forming method.

FIG. 31 is a partial cross-sectional view showing a wire bonding portion according to VII of Embodiment 1 of the present invention.

In this embodiment, the coating film of the coating wire 5 has a composite coating film structure. That is, the outer surface of the covering wire 5 is covered with the covering film 5B made of the above-described heat-resistant polyurethane, and the outer surface of the covering film 5B is further covered with a second covering film 5C made of another insulating material. This is an example of coating with.

As the material of the second coating film 5C, as described above, a polyamide resin, a special polyester resin, a special epoxy resin, or the like can be used. For the purpose of improving the slipperiness of the coated wire in the capillary using nylon or the like, a second coating film can be applied.

Further, the thickness of the second coating film 5C can be set to twice or less, preferably 0.5 times or less of the thickness of the coating film 5B.

As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the embodiments, and it can be said that various modifications can be made without departing from the gist of the invention. Not even.

For example, the materials for forming the coating film 5B or 5C, such as the polyol component, isocyanate, terephthalic acid, and the compounds thereof, and the types and compositions of the additives are not limited to those described above.

Further, the material of the metal wire 5A of the covered wire and the bonding method thereof are not limited to the examples described above.

Further, the structure of the wire bonding apparatus used for carrying out the present invention is not limited to the above-described example.

In the above description, the case where the invention made by the present inventor is applied to a resin-encapsulated semiconductor device as a field of application has been mainly described. However, the present invention is not limited to this. Can be widely applied to various semiconductor devices and their manufacturing techniques.

The effects obtained by typical ones of the inventions disclosed in the above embodiments will be briefly described as follows.

(1) A method for manufacturing a semiconductor device, comprising connecting a lead to an external terminal of a semiconductor chip with a covered wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covered wire is A polyol component and an isocyanate are reacted, the molecular skeleton is made of heat-resistant polyurethane containing a structural unit derived from terephthalic acid, one end of the coated wire is connected to the external terminal of the semiconductor chip, and the other end is connected to a lead. By connecting to the wire, it is possible to prevent the coating film from being destroyed due to thermal deterioration, so that the occurrence of electrical short-circuit failure such as tab short-circuit, chip short-circuit, and short-circuit between wires can be ensured. Can be prevented.

(2) Even if the coated wire is bent, a highly reliable semiconductor device free from wire failure can be obtained without causing cracks or peeling of the coated film.

(3) Since the urethane bond of the heat-resistant polyurethane constituting the coating film is decomposed at the bonding temperature during normal wire bonding or the ultrasonic vibration energy and can be bonded, thermocompression bonding by normal heating and / or ultra Strong bonding can be performed by sonic vibration.

(4) According to the above (3), since the coating film does not carbonize,
It is possible to prevent carbide from hindering the passage of the coated wire to the capillary, to prevent the coated wire from dropping on the integrated circuit and cause an electrical short circuit, and to prevent the carbide from deteriorating the wire bonding property.

(5) According to the above (3), reliable wire bonding can be performed even with a normal wire bonding apparatus. In particular, if the wire bonding apparatus shown in the above embodiment is used, extremely reliable wire bonding can be performed.

(6) When the other end of the covered wire is connected to the lead, only the wire bonding portion of the lead is heated, so that more reliable wire bonding is possible.

(7) By adding a predetermined amount of a colorant to the coating film of the coating wire, the coating film can be melted or removed at the time of forming metal balls or removing by heating without impairing the characteristics of the coating film. Can be visually confirmed, which is useful for bonding control and inspection.

(8) According to the above (1), it is possible to realize a multi-terminal (multi-pin) semiconductor device using a covered wire.

(9) By providing a second insulating coating film on the coating film of the coating wire, it is possible to reliably prevent an electric chute failure.

(10) A method of manufacturing a semiconductor device, comprising connecting a lead and an external terminal of a semiconductor chip with a covered wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covered wire is provided. However, the deterioration rate in reducing the number of times of coating film destruction after 150 hours at 150 ° C. to 175 ° C. is within 20%, and the non-carbonized material is used when forming metal balls or removing the coating film. In addition, since electrical short-circuit failure due to deterioration of the coating film can be reliably prevented and carbonization of the coating film is prevented, as described in (4) above, the coating wire is prevented from passing through the capillary due to the adhesion of carbide. It is possible to prevent carbides from dropping on the surface of the integrated circuit and becoming conductive foreign substances to cause an electrical short circuit failure, and also prevent the bonding property from deteriorating due to the adhesion of carbides.

(11) A semiconductor device in which an external terminal of a semiconductor chip and a lead are connected by a covered wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covered wire comprises a polyol component. React with isocyanate,
By using a heat-resistant polyurethane containing a structural unit derived from terephthalic acid in the molecular skeleton, it is possible to obtain a semiconductor device free from electrical short-circuit failure due to thermal deterioration of the coating film.

(12) A semiconductor device in which external terminals of a semiconductor chip and leads are connected by a covering wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covering wire has a thickness of 150 mm. Degradation rate in the reduction of the number of times of coating film destruction after 100 hours from 100 ° C to 175 ° C is within 20%, and it is made of non-carbonized material when forming metal balls or removing the coating film. Prevents electrical shorts caused by thermal degradation of the film.Also prevents formation of a carbide and prevents the coated wire from passing through the capillary. It is possible to obtain a semiconductor device that can also prevent bonding failure and the like.

(2) Embodiment 2 FIG. 32 is a cross-sectional view showing a configuration of a semiconductor device which is Embodiment 2 of the present invention, and FIG. 33 is a plan view of a main part showing a plan shape of a lead frame used in the above embodiment. FIG. 34 is a cross-sectional view of an essential part showing the internal structure of the semiconductor chip of the above embodiment, and FIG.
The figure is a perspective view showing a wire used in the above embodiment, and FIG.
FIG. 37 is an explanatory view showing the characteristics of the wire, FIG. 37 is a schematic explanatory view showing an intermediate layer forming apparatus used for coating the intermediate layer in the wire of the above embodiment, and FIGS. 38 (a) and (b) are FIG. 39 is an explanatory view showing an apparatus configuration of a wire bonding apparatus used in the above embodiment, FIG. 39 is an explanatory view showing a configuration of a resin molding apparatus used for forming a package of the above embodiment,
FIG. 40 is a plan view showing a mold surface in the resin molding apparatus, FIG. 41 is an explanatory diagram showing a relationship between a coefficient of thermal expansion and a compounding amount of a filler, and FIG. 42 is a view showing a resin viscosity and a filler in a molten state. FIG. 43 is an explanatory diagram showing the relationship between the occurrence rate of wire short-circuits and the amount of filler in comparison with the prior art, and FIG. 43 is a thermal cycle at a predetermined defective rate. Table 44 shows the number of times compared with the prior art. Fig. 44 is an explanatory diagram showing the change of the immersion state of water in PCT (pressure cooker test) in comparison with the prior art.
9 is a table showing the change in the number of defective occurrences with respect to the number of samples using specific products in T.

As shown in FIG. 32, the semiconductor device 201 of this embodiment
A semiconductor chip 204 mounted on a tab 202 via a resin paste 203 is provided, and the periphery thereof is sealed with a resin 205 such as an epoxy resin. Inside the sealing, the inner end (inner lead) of the lead 206 led out of the package is located around the semiconductor chip 204, and the inner end surface and the semiconductor chip 20 are separated.
4 is connected with a wire 207 stretched in a loop shape. Details of the connection by the wire 207 will be described later. The lead 206 is led out from the side surface of the package, and is bent into an S-shaped cross section.

Before the resin molding step, the tab 202 and the lead 206 are connected to the lead frame 208 as shown in FIG.
Provided in a state.

That is, the lead frame 208 has a tab 202 supported by a tab suspension lead 210 at the center thereof, and the lead 202 is radiated around the tab 202 radially without contact with the tab 202.
206 has been extended.

The lead frame 208 having such a shape is obtained by etching a conductive plate-like member having a thickness of about 0.15 mm made of, for example, an iron-nickel (Fe-Ni) alloy, Kovar, 42 alloy, or the like by etching or press punching. It can be obtained by processing into a shape. Note that tab 202 or lead 2
Gold (Au), solder, or the like may be applied to the inner end surface of 06.

The semiconductor chip 204 mounted on the tab 202 via the resin paste 203 has a schematic structure shown in FIG. That is, a silicon oxide film 212 of about 0.45 μm is formed on an upper layer of a chip substrate 211 made of silicon (Si) having a thickness of about 400 μm, and a PSG film 213 as an interlayer insulating film is further formed on the silicon oxide film 212 of about 0.35 μm. It is formed with a thickness of about μm. Further, a passivation film 214 as a protective film is deposited on the uppermost layer with a thickness of about 1.2 μm, and a part of the passivation film 214 is made of aluminum (Al) partially provided in the lower layer in an open state. External terminals 215 (bonding pads) having a thickness of about 0.8 μm are exposed upward.

As shown in FIG. 35, the wire 207 connecting the external terminal 215 and the inner end surface of the lead 206 has a structure including a first intermediate layer 216A and a second intermediate layer 216B in this embodiment. Has become. In the following description, when the first and second intermediate layers are collectively referred to, they are simply referred to as an intermediate layer 216.

Gold (Au), copper (Cu), or aluminum (Al) is used as the metal wire 217 forming the axis of the wire 207.

In the wire 207 of this embodiment, a metal wire 217 serving as an axis
Has a diameter of about 25 μm, and an intermediate layer 216 having a two-layer structure formed therearound has a thickness of about 2 μm. Therefore, the diameter of the entire wire 207 is 29 to 30
μm. Thus, the total diameter of the entire wire 207 is 3
The reason why the thickness is set to 0 μm or less is that in a wire structure having a diameter larger than this, the resistance pressure during resin molding described later increases, and the possibility of disconnection of the wire 207 increases. However, this does not mean that wires of 30 μm or more cannot be used.

First intermediate layer 216A provided around metal wire 217
In this embodiment, a heat-resistant polyurethane resin is used, which is formed by reacting a polyol component with an isocyanate, and has a molecular skeleton containing a structural unit derived from terephthalic acid. First intermediate layer 216A
The use of a heat-resistant polyurethane resin having such a composition is extremely useful for improving the thermal degradation and bonding property of the first intermediate layer 216A, and improving the peeling strength of bonding.

Specific characteristics of the first intermediate layer 216A include a temperature cycle test or a wear test under the experimental conditions shown in FIG.
It is important to select a material that satisfies the condition that the degradation rate in reducing the number of times of destruction of the intermediate layer after 100 hours is within 20%.

Furthermore, it is necessary that when performing the experimental wire bonding operation with the wire 207, no defect occurs in the bonding property. According to the research results of the inventor of the present invention in this regard, it is desirable that the intermediate layer 216 be formed of a material that is non-carbonizable when the intermediate layer 216 is removed by heating during formation of the metal ball 218 described later.

The reason is as follows. That is, a metal ball
In the heat removal of the intermediate layer 216 during the formation of the 218, the intermediate layer
216 melts above the metal balls 218. At this time, if the intermediate layer 216 is carbonizable, the intermediate layer 216 is not decomposed and carbonized at a heating temperature, for example, a high temperature condition of about 1060 ° C. Will be. As a result, the carbonized intermediate layer 216 adheres to and remains on the surface of the metal wire 217 so as to wrap the metal wire 217 immediately above the metal ball 218.
In the worst case, it may cause wire curl or even break.

Considering this fact comprehensively, the wire 20
It is necessary for the first intermediate layer 216A of No. 7 to satisfy at least the following two conditions.

That is, first, through a temperature cycle test or a wear test under the experimental conditions shown in FIG.
Degradation rate in reducing the number of times of destruction of the intermediate layer after 100 hours under the temperature condition of ℃ is 20% or less.

Second, the intermediate layer 216 is made of a material that is non-carbonizable when the intermediate layer 216 is removed by heating when the metal ball 218 is formed.

The heat-resistant polyurethane as a constituent material of the first intermediate layer 216A that satisfies the above conditions will be described more specifically. The heat-resistant polyurethane includes a polymer component mainly containing a terephthalic acid-based polyol containing active hydrogen,
And isocyanates. Note that
Here, “consists of the main component” is intended to include the case where the whole is composed only of the main component.

Terephthalic acid-based polyol containing the active hydrogen, terephthalic acid and polyhydric alcohol, using OH / COO
In the range of H = 1.2-30, set the reaction temperature to 70 ° C-250 ° C,
It can be obtained by a conventional ester chemical reaction. Generally, the average molecular weight is in the range of 30 to 10,000 and the hydroxyl group is 100 to 500.
The one having a hydroxyl group at both ends of the molecular difference is used.

Raw materials constituting such a terephthalic acid-based polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Hexane glycol, butane glycol, glycerin,
Aliphatic glycols such as trimethylolpropane, hexanetriol and pentaerythritol;
In addition to the above, polyhydric alcohols such as 1,4-dimethylolbenzene can be used. Especially in the above,
It is preferable to use ethylene glycol, propylene glycol, and glycerin.

Terephthalic acid is used as the dicarboxylic acid. If necessary, amic acid and imidic acid can be used in combination.

Further, to the extent that the heat resistance is not reduced, diphthalic acid, orthophthalic acid, succinic acid, adivisic acid, dibasic acids such as sebacic acid, or 1,2,3,4-butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, Polybasic acids such as ethylenetetracarboxylic acid, pyromellitic acid and trimellitic acid may be used in combination.

As the isocyanate to be reacted with the terephthalic acid-based polyol, at least two isocyanates in one molecule such as toluylene diisocyanate and xylylene diisocyanate are used.
Examples thereof include those obtained by blocking an isocyanate group of a polyvalent isocyanate having two isocyanate groups with a compound having active hydrogen, for example, a phenol, caprolactam, or methyl ethyl ketone oxime. Such isocyanates are stabilized. Also,
Examples thereof include those obtained by reacting the above polyvalent isocyanate compound with a polyhydric alcohol such as trimethylolpropane, hexanetriol, or butanediol, and blocking with a compound having active hydrogen.

Examples of the isocyanate compound, manufactured by Nippon Polyurethane Co., Millionate MS-50, Coronate 2501,250
3,2505, Coronate AP-St, Death Module CT-St and the like. It is preferable to use a polyisocyanate having a molecular weight of about 300 to 10,000.

In the present invention, a coating composition is prepared by using the above-described raw materials, and the coating composition is applied to the metal wire 217 of the wire main body.
With this thickness, the wire 207 insulated around the metal wire 217 of the wire 207 main body is obtained. For such coating, an intermediate layer forming apparatus shown in FIG.
It is possible to use 220.

As the coating composition, the hydroxyl group 1 of the polyol component is used.
Per equivalent, isocyanate groups of the stabilized isocyanate
0.4 to 4.0 equivalents, preferably 0.9 to 2.0 equivalents and a required amount of a curing accelerator are added, and an appropriate amount of an organic solvent (phenols, glycol ethers, naphtha, etc.) is further added. % By weight. At this time, if necessary, an appropriate amount of an additive such as an appearance improving agent and a dye can be blended.

In the present invention, the isocyanate group of the stabilized isocyanate is 0.4 to 0.4 per hydroxyl equivalent of the polyol component.
The reason for adding 4.0 equivalents is that, first, if it is less than 0.4 equivalent, the crazing property of the obtained insulated wire 207 is reduced, while
This is because the abrasion resistance of the coating film exceeding the equivalent becomes inferior. The curing acceleration catalyst added at the time of preparing the coating composition is preferably 0.1 to 10 parts by weight per 100 parts by weight of the polyol component. Also, when it is less than 0.1 part by weight, the effect of curing promotion is reduced and the tendency to form a coating film tends to be deteriorated, and when it exceeds 10 parts by weight, the heat deterioration property of the obtained heat-resistant urethane bonding wire is reduced. This is because a decrease is observed.

Examples of the curing acceleration catalyst include metal carboxylic acids, amino acids, and phenols.Specifically, naphthenic acid, octenoic acid, zinc salts such as persatic acid, iron salts, copper salts, manganese salts, cobalt salts, A tin salt, 1,8 diazabicyclo (5,4,0) undecene-7,2,4,6 tris (dimethylaminomethyl) phenol is used.

The coating composition as described above can be obtained by applying the coating composition on the surface of the metal wire 217 of the wire main body by using an intermediate layer forming apparatus 220 described later, and baking it by using a baking apparatus 221 described below.

The coating and baking conditions vary depending on the amounts of the polyol component, the stabilized isocyanate, the polymerization initiator and the curing accelerator, but are usually about 200 to 300 ° C. for about 4 to 100 seconds. In short, baking is performed at a temperature and for a time sufficient to substantially complete the curing reaction of the coating composition, and the wire 207 of this embodiment is obtained.

According to the study results of the present inventors, the first intermediate layer
As a constituent material of 216A, in addition to the heat-resistant polyurethane having the above-described composition, a commercially available polyurethane, and formal also satisfy the requirement of non-carbonization, but under the above-mentioned conditions in reducing the number of times of destruction of the intermediate layer after 100 hours at 150 ° C. to 175 ° C. Is not optimal as the first intermediate layer 216A.

On the other hand, polyimide, polyamide, nylon, polyester, polyamide imide, polyester imide, and the like exhibit carbonization when the metal ball 218 is formed or when the first intermediate layer 216A is removed by heating.
It became clear that it was not optimal for use as A because of its drawbacks.

The second intermediate layer 216B formed around the first intermediate layer 216A is made of fluororesin in this embodiment. The fluororesin has excellent releasability with another resin such as an epoxy resin constituting a package. For this reason, after the resin molding described later, the wire 20
7 is in a state in which it can be finely moved in the cured resin 205, and the wire 207 is prevented from being disconnected even when the shape of the resin 205 as a package changes due to thermal stress.

That is, assuming that the wire 207 has a structure including only the first intermediate layer 216A, first, in such a wire structure, the heat-resistant polyurethane resin and the resin 205 constituting the first intermediate layer 216A are used. Since the adhesiveness with the epoxy resin is too good, the wire 207 follows the deformation due to a slight thermal stress. Therefore, when a wire flow occurs and the resin molding is performed while the tab 202 or the semiconductor chip 204 and the first intermediate layer 216A of the wire 207 are in contact with each other, slight thermal stress deformation of the resin 205 causes There is a high possibility that the wire 207 will also break.

Regarding this point, according to the present embodiment, since the second intermediate layer 216B is provided around the first intermediate layer 216A by the fluororesin having good mold release properties, the resin 205 remains in the resin 205 even after the resin molding. Allows fine movement of the wire 207. For this reason, the wire 2
07 does not follow, and the disconnection of the wire 207 is effectively prevented.

Regarding the formation of the second intermediate layer 216B described above,
This is realized by applying a fluorine resin in a molten state around the first intermediate layer 216A.

Next, the above-described first and second intermediate layers 216A, 216B
Will be described in detail.

The intermediate layer forming apparatus 220 of this embodiment includes a first storage tank 222A and a second storage tank 222B as shown in FIG. 37, and the storage tanks 222A and 222B have Are respectively arranged. The internal structure of the storage tanks 222A and 222B will be described below. Unless otherwise specified, the first storage tank 222A and the second storage tank 222B are collectively referred to as a storage tank 222, and the same reference numerals are used. Simplify the description. Inside the storage tank 222, a storage liquid 223 is stored at the bottom thereof, and a wire passing space 225 is formed above the storage liquid 223. Here, the storage liquid 223 is a solution of a heat-resistant polyurethane resin which is a raw material constituting the first intermediate layer 216A in the first storage tank 222, and is a second intermediate liquid in the second storage tank 222. This is a fluororesin solution for forming the layer 216B. In addition, heating means 224 such as a heater for maintaining the liquid state of the stored liquid 223 is disposed around the storage tank 222.

Inside the storage tank 222, a plurality of pulleys 226 that are rotatable in a vertical plane along a sending direction of the wire 207 passing through the tank are arranged in the wire passage space 225. The pulley 226 is arranged such that the lowermost part thereof is always immersed in the storage liquid 223, and a wire 207 (metal wire 217) as an object to be coated is hung on the uppermost part.
In the present embodiment, the pulley 226 is freely rotatable around the pivot 227, and the pulley 226 is rotated in conjunction with the axial movement of the wire 207 passing through the storage tank 222. It has a configuration.

Therefore, a part of the pulley 226 immersed in the storage liquid 223 by the rotation of the pulley 226 rotates and moves to the upper wire passage space 225 while leaving a predetermined amount of the storage liquid 223 on the pulley surface, and further, the wire 207 It will be in contact. At this time, the storage liquid 223 on the pulley surface is applied around the wire 207. The baking device 221 disposed on the side of the storage tank 222 has a built-in heating source such as an infrared lamp or a cartridge heater, for example. The baking device 221 converts the storage liquid 223 applied around the wire 207 in the storage tank 222. The material is cured to a predetermined state by heating. Thus, in this embodiment, the metal wire 2 is moved only by moving the wire 207 in the axial direction.
A storage liquid 223 can be applied around the periphery of 17 and baked to form the intermediate layer 216. In this embodiment, since the first storage tank 222 and the second storage tank 222 are continuously arranged, the intermediate layer 216 having a two-layer structure including the first intermediate layer 216A and the second intermediate layer 216B is formed. It can be produced very efficiently.

In the above description, the first storage tank 222 and the second storage tank 222 are illustrated and described as each having a single tank structure. However, for example, when a predetermined layer thickness cannot be realized with this alone,
The storage tank 222 has a plurality of divided tank structures, and the plurality of pulleys 226 are continuously arranged in the axial direction of the wire 207 to form the same storage liquid 2.
The layer thickness can be increased by applying 23 multiple times.

Next, a wire bonding step using the wire 207 obtained through the intermediate layer forming device 220 will be described.

As shown in FIG. 38, the wire bonding apparatus 230 used in this wire bonding process includes an XY stage 2 on which a bonding head 231 as a driving mechanism is mounted.
32, a bonding stage 233 on which the lead frame 208 is mounted, and a control unit 234 for controlling these operations.

The control unit 234 performs overall control of the wire bonding apparatus 230, and is configured by, for example, a microcomputer system having a microprocessor or a memory, and is capable of performing a bonding operation according to operating conditions set by an operator. .

The bonding stage 233 has a heating source such as a heater, and has a structure in which the lead frame 208 mounted on the bonding stage 233 is heated to a predetermined temperature condition.

On the other hand, inside the bonding head 231 on the XY stage 232, a vertically moving block 235 is arranged so as to be able to move up and down along a guide shaft 236 provided in a direction perpendicular to the XY stage 232. A ball screw mechanism 238 that converts the rotation of a servo motor 237 fixed to the bonding head 231 into a linear motion in the vertical direction is provided on a side surface of the 235. Therefore, the vertical movement block 235 can be moved up and down by a predetermined amount with the rotation of the servomotor 237.

The vertical movement block 235 has a bonding arm 240 rotatable in a vertical plane about a rotation axis, and a rear end of the bonding arm 240 is provided with an elastic means such as a spring fixed to the vertical movement block 235. 241 urged upward in FIG.
With the operation of, a counterclockwise urging force acts on the bonding arm 240.
The elastic means 241 prevents the external terminal 215 from being overpressurized when the bonding tool 243 comes into contact with the external terminal 215 of the semiconductor chip 204, and prevents the occurrence of these damages and destructions. It is configured as follows.

Similarly, an ultrasonic oscillator 242 is provided at the rear end of the bonding arm 240, and has a structure capable of transmitting predetermined ultrasonic energy to the bonding arm 240. In the present embodiment, the ultrasonic oscillator 242
Is controlled by the control unit 234.

At the tip of the bonding arm 240 to which the ultrasonic energy is transmitted, a bonding tool 243 is disposed vertically downward. This bonding tool 243
The airbag tensioner 24 from the wire spool 244
5. The wire 207 supplied via the sprocket 246 and the clamper 247 is inserted with its tip slightly protruding.

The tip of the bonding tool 243 has a bonding space 251 separated by a cover 250 interlocked with an electric torch 248, and a fluid spray nozzle 252 protrudes into the bonding space 251. This fluid spray nozzle 252
Is connected to a fluid source so that a cooling fluid 253 such as nitrogen gas or ion gas can be supplied to the bonding space 251.

The electric torch 248 is provided with a suction port 254 on the torch surface, and the suction port 254 is connected to a suction pipe 255 that supports the electric torch 248. The suction tube 255 is further supported by a support member 256, and the support member 256 has a structure rotatable by a rod 258 and a crank shaft 260 protruding from a drive source 257 formed of an electromagnetic solenoid or the like. In addition, the cover 250 and the electric torch 248 can be arranged at the tip of the bonding tool 243 only when necessary at the time of wire bonding.

In the above-described apparatus configuration, first, when the XY stage 232 is operated in a state where the lead frame 208 is positioned and arranged on the bonding stage 233, the bonding head 231 is horizontally moved by a predetermined amount, and the bonding tool 243 is moved. Is located immediately above the semiconductor chip 204 by a predetermined amount.

In this state, the drive source 257 operates and the suction tube 255 moves,
The tip portion of the bonding tool 243 is covered by the cover 250.

Next, with respect to the electric torch 248, -1000 to -3000 [V]
When the negative high voltage is applied, the electric torch 248
An arc discharge occurs between the wire 207 and the wire 207, and the tip of the wire 207 (metal wire 217) is melted to form a spherical metal ball 218 (FIG. 38 (b)). At this time, the intermediate layer 216 formed around the wire 207 by the heat of the arc discharge,
The wire 207 melts upward from the tip portion, and the intermediate layer 216 in this portion is removed, leaving the surface of the metal wire 217 exposed.

It is desirable that the formation of the metal ball 218 be performed in as short a time as possible. At this time, by forming the metal balls 218 with high energy (high current, high voltage), the amount of the intermediate layer 216 melted can also be suppressed. Such a state is realized by stabilizing the state of the arc discharge.
In this regard, the electric torch 248 is
The state of the arc discharge is stabilized by fixing and holding the metal wire 217 of one of the wires 207 at the reference potential (GND = 0 [V]) at a negative potential of about -3000 [V]. be able to.

Further, at the time of forming the metal balls 218, the cooling fluid 253 is supplied to the bonding space 251 surrounded by the cover 250 through the fluid spray nozzle 252. This cooling fluid 253 is configured to be sprayed on the wire 207 in the bonding space 251 so that the metal wire
The melted intermediate layer 216 around the 217 is scattered, and the scattered intermediate layer 216 is removed to the outside of the system through the suction port 254 and the suction pipe 255 of the electric torch 248. The cooling fluid 253 from the fluid spray nozzle 252 is cooled by a cooling device, for example, to about −10 to 0 ° C., and the lower the temperature of the cooling fluid 253 from the fluid spray nozzle 252 at this time, the more the wire 207 becomes. The amount of melting of the intermediate layer 216 is reduced.
That is, the metal wire 21 of the wire 207 is cooled by the cooling fluid 253.
7. Since the intermediate layer 216 and the bonding tool 243 can be actively cooled, the intermediate layer 216 at the arc discharge portion is not affected (without excessive melting) without affecting other intermediate layer 216 portions. Only can be melted.

After the metal ball 218 is formed as described above, the drive source 257 is operated again, the suction pipe 255 is rotated, the cover 250 is detached from the periphery of the bonding tool 243, and the tip of the bonding tool 243 is It becomes open.

In this state, the servo motor 237 of the bonding head 231 is
When the ball screw mechanism 238 is moved downward by a predetermined amount, the bonding tool 243
04 lands on the surface of a predetermined external terminal 215 (No. 34
Figure).

When the ultrasonic oscillator 242 is operated under the control of the control unit 234 in the landing state, the ultrasonic energy is transmitted to the bonding tool 243 via the bonding arm 240.

At this time, due to the synergistic effect of the urging force of the vertical movement block 235, the ultrasonic energy, and the heating from the bonding stage 233, the metal ball 218 is joined to the external terminal 215 (first bonding). .

Next, when the servomotor 237 is driven in a state where the application of the ultrasonic energy is maintained, the bonding tool 243 moves upward above the semiconductor chip 204. At this time, since the distal end (metal ball 218) of the wire 207 is fixed to the external terminal 215 as described above, the wire 207 is sent out by a predetermined amount as the bonding tool 243 is raised.

Subsequently, when the XY stage 232 is operated, the bonding tool 243 moves in a horizontal direction along a path shown by a two-dot chain line in FIG. Also at this time, the wire 207 is sent out from the tip of the bonding tool 243. At this time, the wire 207 may be deformed such as bending in the bonding tool 243, but according to the present embodiment, the application of ultrasonic energy to the bonding tool 243 is continuously performed when the wire 207 is sent out. As a result, the deformation of the wire 207 in the bonding tool 243 is prevented. Further, the continuous application of the ultrasonic energy facilitates the feeding of the wire 207, so that the wire 2
The damage and disconnection of 07 are also prevented.

Next, when the bonding tool 243 is lowered in the Z-axis direction by the operation of the servomotor 237, the tip of the bonding tool 243 lands on the inner end surface (inner lead) of the lead 206 with the wire 207 being led out. The ultrasonic energy continued in this state
The abdomen of 207 is in vibration contact with the inner end surface of the lead 206, and a part of the intermediate layer 216 is broken and removed. When the application of ultrasonic energy is continued, the exposed metal wire 217 is ultrasonically bonded to the inner end surface of the lead 206. (Second bonding).

Thereafter, the extra portion of the wire 207 is cut, and one cycle of wire bonding is completed.

Next, a resin molding process performed on the lead frame 208 on which wire bonding has been completed as described above will be described together with an apparatus used for the resin molding process.

The resin molding apparatus 216 used in the present embodiment is a
As shown in the figure, it has an upper mold part 263 held by an upper fixed platen 262 and a lower mold part 265 supported by a lower movable platen 264. In the upper mold part 263 and the lower mold part 265, the molds 266 shown in FIG. 40 are arranged with their division forming surfaces (parting surfaces) facing each other. It will be described later.

The fixed platen 262 is supported above the stage by a plurality of columns 268 suspended from the apparatus base 267, and the raw material of the resin 205 is supplied in the form of a tablet 263 to the upper part of the fixed platen 262. A transfer cylinder 264 is provided. The above transfer cylinder 264
Is connected to a pot 265 provided in the upper mold part 263, and has a structure capable of pressing the plunger. A platen driving cylinder 268 for moving the movable platen 264 up and down is arranged below the apparatus base 267, and the platen driving cylinder 268 is controlled by a control unit 269 arranged on the side of the stage.

The mold 266 shown in FIG. 40 is made of a metal member such as die steel capable of withstanding a molding temperature of, for example, about 180 ° C., and a plurality of culs 270 corresponding to the pot 265 are arranged on the parting surface. Have been. As is clear from the figure, the resin molding apparatus 261 of the present embodiment is of a so-called multi-pot type having a plurality of pots 265. The cull 270 has a runner 271 formed in a groove shape on the parting surface, and the tip of the runner 271 is attached to a detachable chase unit 272.
The runner 271 is in communication.

The chase unit 272 has a plurality of cavities 274 via the runner 271 and a gate 273 communicating therewith, and the lead frame 208 is mounted on the cavity 274 as an object to be molded. Thereby, resin molding can be performed in a predetermined range.

Next, components of the resin 205 which is a raw material of the package used in the present embodiment will be described.

The resin 205 is composed of an epoxy resin composition, and contains a general epoxy resin such as a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, a bisphenol A type epoxy resin as a main component, and a filler and the following additives. It is blended. Examples of additives include a phenol novolak resin as a curing agent that cures by a crosslinking reaction, tertiary amines as a curing accelerator for accelerating curing, and Br as a flame retardant for flame retarding resin 205. Epoxy-containing, epoxysilane as a coupling agent to improve adhesion between resin 205 and filler, stearic acid or wax as a release agent to facilitate release from mold 266 after curing, coloring agent As carbon black.

At this time, the amount of the release agent added can be as large as 0.3 to 0.8% by weight, preferably 0.4 to 0.6% by weight in the form of resin or tablet. Thus, even if the release agent is increased, the adhesiveness between the coated lead and the resin is good, so that the mold yield can be improved without lowering the moisture resistance.

In this embodiment, the filler contains fused silica powder. In such a fused quartz powder, when 90% by weight or more of the filler is in the range of particle size of 100 μm or less, and the particle size distribution is shown by an RRS particle size diagram, the gradient n is 0.6 to 1.
It is a spherical shape showing linearity in the range of 5, which is blended at 65 to 75% by weight based on the whole resin.

Here, the RRS particle size diagram is the following rosin-Rammler (R
osin-RAmmler).

R (Dp) = 100exp (−b = Dpn) (where R (Dp) is the cumulative weight% from the maximum particle size to the particle size Dp, Dp is the particle size, and b and n are constants) In the above equation, R (Dp) is also referred to as the accumulated residual weight%.

The gradient in the RRS particle size diagram means that the cumulative weight% up to the maximum particle size Dp of the RRS particle size diagram is at least 25% by weight and 75%.
It means the n value of the Rosin-Rammler equation represented by a straight line connecting two points in the range of weight%. Generally, when a filler ore is finely pulverized, its particle size distribution conforms to the rosin-Rammler equation, and it is considered that the RRS particle size diagram, which is a method of expressing the particle size distribution based on this equation, shows almost linearity. ing.

Spherical fused silica powder having such a particle size distribution can be obtained by, for example, as disclosed in Japanese Patent Application Laid-Open No. 59-59737, by melting a fused quartz powder in a square state previously ground to a predetermined particle size distribution with propane and butane. It is obtained by supplying a fixed amount into a high-temperature flame generated from a thermal spraying device using hydrogen or the like as a fuel, melting and cooling.

90% by weight or more particle size as filler in epoxy resin
It is within the range of 100 μm or less, and its particle size distribution is
A spherical fused silica powder showing a linearity in the range of 0.6 to 1.5 when the gradient n is displayed in the RS particle size diagram is applied to the entire resin.
Resin 205 containing 65 to 75% by weight has a coefficient of thermal expansion of 10 × 1
It can be set to 0 ^-6 / ° C or less.

In general, it can be easily understood that the amount of the filler in the entire resin should be increased in order to set the thermal expansion coefficient to the above value. FIG. 41 shows the relationship between the coefficient of thermal expansion of the resin 205 and the blending amount of the filler. It is understood from FIG. 3 that the thermal expansion coefficient of the entire resin can be suppressed by increasing the amount of the filler. According to the figure, the coefficient of thermal expansion of the resin 205 is 1
In order to achieve 0 × 10 ⁻⁶ / ° C., the amount of the filler needs to be about 75% by weight.

However, according to FIG. 42 showing the relationship between the melt viscosity of the resin 205 and the blending amount of the filler, the expansion coefficient of the resin 205 was 1
The melt viscosity of the resin 205 at 0 × 10 ⁻⁶ / ° C. is 10.000
(Poise), and when the resin molding process is performed in such a high viscosity state, the flow (deformation) of the bonded wire 207 occurs due to the resin viscosity, and a wire short, a tab touch short, This causes bonding failure such as chip touch short-circuit. FIG. 43 shows the relationship between the occurrence rate of such a wire short and the compounding amount of the filler. In the same figure, when the conventional wire 207 consisting of only the metal wire 217 is used, when the compounding amount of the filler is 75% by weight, the occurrence rate of the wire short is as high as 5%. .

However, in the wire 207 provided with the intermediate layer 216 of the present embodiment, when the compounding amount of the filler is in the range of 60 to 75% by weight, the occurrence rate of the wire short-circuit is almost nil.
Due to the construction of the wire 207 with 6
It can be understood that the suppression of the expansion coefficient of 5 is realized.

That is, in the present embodiment, the intermediate layer 216 is provided around the metal wire 217.
Is provided, the wire 207 is connected to another wire, the tab 2
Even in the case of contact with the semiconductor chip 204 or the semiconductor chip 204, the intermediate layer 216 maintains electrical insulation. Therefore, even if a slight wire flow occurs,
Electrical shorts are reliably prevented. Therefore, the thermal expansion coefficient of the semiconductor chip 204 or tab 202 and the lead 20
A package structure similar to the thermal expansion coefficient of 6 can be realized,
Peeling of the resin interface based on the difference in the thermal expansion coefficient, that is, cracking of the resin 205 is effectively prevented.

The spherical shape of the fused quartz powder used as the filler is intended to reduce the bulk as the filler to achieve high filling, and to prevent damage to the chip surface due to contact with the corner chip surface. This is to prevent it. The reason for using fused quartz powder is that fused quartz is easily available, has a relatively small coefficient of thermal expansion itself, and is effective in reducing the thermal expansion of the resin 205 as a whole. Further, since fused quartz has a very low content of ionic impurities, it prevents contamination of the chip surface and has little effect on element characteristics.

The resin 205 is kneaded with a twin-screw roll or an extruder heated to 70 to 100 ° C., and a semi-molten tablet 26 is prepared.
After being set to 3, it is put into the resin molding apparatus 261.

Next, the heaters incorporated in the upper mold part 263 and the lower mold part 265 are operated, and the mold 266 is heated to a predetermined temperature of about 180 ° C. In this state, when the lead frame 208, which is the object to be molded, is placed between the upper mold part 263 and the lower mold part 265 in a fixed state, the platen driving cylinder 268 is controlled by the control unit 269. The movable platen 264 is raised and the upper mold part 263 and the lower mold part 265 are closed.

Thus, in a state where both mold parts 263 and 265 are closed, the mold clamping force is controlled to, for example, about 150 (T).

Next, when the transfer cylinder 264 is operated and a transfer pressure of about 75 (Kgf / cm ² ) is applied to the tablet 263, the tablet 263 is brought into a molten resin state from the runner 271 in a molten resin state by a synergistic effect with the heating. And gate 273
Through the cavity 274.

At this time, according to the present embodiment, the molten resin, that is, the resin 205, has a thermal expansion coefficient of 10 as described above.
In order to realize × 10 ⁻⁶ / ° C., the amount of the filler is increased to 75% by weight (see FIG. 41). Accordingly, as shown in FIG. 42, the viscosity is also a high value of 10,000 poise or more. Such high viscosity resin 20
Injection into cavity 274 using 5
Clogging of runner 271 by 205 and wire flow can occur. In order to solve the former problem, in the present embodiment, a multi-pot system is adopted, the path of the runner 271 from the cull 270 to the cavity 274 is shortened, and each cavity 274 is formed by a plurality of pots 265 (resin supply source). , The transfer pressure in each plunger can be efficiently transmitted to the resin 205.

For the latter, the present embodiment has a wire structure including a two-layered intermediate layer 216 made of an insulating resin.
Some wire flow, wire-to-wire or wire-to-wire
Even when the 207, the tab 202, and the semiconductor chip 204 come into contact with each other, an electrical short is effectively prevented. As described above, since the present embodiment has a structure in which the insulating intermediate layer 216 is provided around the metal wire 217, the wires 207 can be connected without fear of contact between the wires 207 or between the wires 207 and the tabs 202 and the semiconductor chip 204. Since bonding can be performed,
Conventional metal wire 217 (bare wire) such as cross bonding as shown in FIG. 33A or bonding across the tab suspension lead 210 as shown in FIG.
This makes it possible to perform complicated wire bonding, which has been difficult in such a case, and promotes high functionality and high integration of the semiconductor device 210.

The lead frame 208 having the package formed by the resin 205 as described above is cooled to a predetermined temperature in the mold 266, and after the resin 205 is cured, the mold 2
66 taken out.

The package of the semiconductor device 201 thus obtained has a coefficient of thermal expansion controlled to 10 × 10 ⁻⁶ / ° C., and has a value approximately similar to the coefficient of thermal expansion of the lead frame 208. For this reason, even when a thermal cycle is performed after the resin molding, the occurrence of cracks due to the difference in thermal expansion coefficient is effectively prevented.

Table 3 shows the number of heat cycles until the crack failure between the resin 205 used in the present embodiment and the resin 205 according to the prior art reaches 10%. As is clear from the table,
In this embodiment, the thermal expansion coefficient of the resin 205 is 10 × 10
^-6 , the number of cycles leading to the crack failure of 10% was 300 cycles. However, when the resin 205 of the prior art was used, for example, the coefficient of thermal expansion was 19
Because of a large value of × 10 ^-6 , crack failure reached 10% in only 20 cycles.

In addition, since cracks are suppressed as described above, intrusion of moisture caused by gaps due to cracks is also suppressed. FIG. 44 shows the PCT of the semiconductor device 201 obtained according to the present embodiment and the semiconductor device according to the prior art.
4 shows the relationship between the distance of penetration of moisture into a package and time when (pressure cooker test) is performed. According to the figure, in the conventional semiconductor device, about 3000
Although the moisture (fluorescent liquid) has reached the semiconductor chip over time, in the semiconductor device 201 of this embodiment, 100
Even after the elapse of 0 hours, the intrusion of moisture has reached only about half of the distance from the outer edge of the package to the semiconductor chip 204. As described above, this embodiment has a remarkable effect also on the corrosion resistance.

On the other hand, Table 4 shows this embodiment as a specific product of a 4-megabit DRAM (package structure is SOJ: Small Out-line J).
This is a comparison between a case where the present invention is applied to the conventional technology and a case where the conventional technology is used, and shows the number of defective ICs in comparison with the total number of ICs. According to the table,
In the above PCT (pressure cooker test)
In the prior art, a defective IC occurs after about 500 hours, whereas in the present embodiment, a defective IC occurs even after 1000 hours.
Was not detected. As described above, according to the present embodiment, the moisture resistance reliability is greatly improved by the synergistic effect of the wire structure provided with the intermediate layer 216 made of the insulating resin and the package structure of the resin 205 having the suppressed thermal expansion coefficient. I have.

Further, in this type of wire structure including the intermediate layer 216 made of an insulating resin, the adhesion between the intermediate layer 216 and the resin 205 is too high, especially when the wire 207 has a chip touch. There is a concern that the metal wire 217 inside the intermediate layer 216 may be broken even by a change in the thermal stress of the resin 205. However, according to the present embodiment, the intermediate layer 216
Is a first intermediate layer 216A made of heat-resistant polyimide resin
And a second intermediate layer 21 made of a fluororesin having excellent release properties.
6B, the second intermediate layer 21
Even when a thermal stress is applied to the package by the release action of 6B, the wire 207 does not follow the deformation of the package, and the disconnection is prevented.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the invention. Nor.

For example, the case where the second intermediate layer 216B is made of a fluorine resin has been described as an example, but another release agent such as a silicone resin or silicone grease may be used.

The following is a brief description of an effect obtained by the representative one of the inventions disclosed in the present embodiment.

That is, in the resin constituting the package, it is possible to effectively prevent the occurrence of cracks based on the difference in the coefficient of thermal expansion.

In addition, the disconnection of the wire caused by the thermal stress in the package can be effectively prevented.

As described above, a highly reliable resin-molded semiconductor device can be provided.

(3) Embodiment 3 FIG. 45 (partial sectional view) and FIG. 46 (partial sectional plan view) show the structure of a DIP-type resin-sealed semiconductor device which is I according to Example 3 of the present invention. Show. FIG. 45 is a cross-sectional view of a principal part of the resin-sealed semiconductor device shown in FIG. 46, taken along the line II.

As shown in FIGS. 45 and 46, the DIP-type resin-sealed semiconductor device 301 includes an external terminal (bonding pad BP) 302E of a semiconductor chip 302 and an inner lead 303 of a lead 303.
B is connected with a covering wire 305.

The semiconductor chip 302 is a DRAM in which a series circuit of a memory cell selection MOSFET and an information storage capacitor is used as a memory cell.
It is composed of (D ynamic R andom A ccess M emory). In the semiconductor chip 302, as shown in FIG. 45, a large number of semiconductor elements including the memory cells are integrated on a main surface of a single crystal silicon substrate 302A. Each semiconductor element has its shape defined by an element isolation insulating film (field insulating film) 302B formed between the respective regions and is electrically isolated.

An interlayer insulating film 30 is formed on the element isolation insulating film 302B.
2C, an interlayer insulating film 302D, an external terminal 302E, a protective film (passivation film) 302F, and a barrier metal film 302H are sequentially laminated.

An interlayer insulating film 302C is a first layer connecting the semiconductor element (eg, a gate electrode or a word line of a MOSFET) and the semiconductor element.
It is configured so as to be electrically separated from a layer wiring (for example, a data line). The interlayer insulating film 302D is configured to electrically separate the first layer wiring and the second layer wiring (for example, a shunt wiring short-circuited with the word line). This second layer wiring constitutes the external terminal 302E.

A barrier metal film 302H is formed on the surface of the external terminal 302E. This barrier metal film 302H is a protective film 302F.
Through the opening 302G formed in the external terminal 302E.

The semiconductor chip 302 thus configured is mounted on the surface of the tab 303A of the lead 303 with an adhesive metal (for example, an Au-Si eutectic alloy or Ag paste) 302 interposed therebetween.
The lead 303 is formed of, for example, an Fe-Ni alloy (for example, an alloy containing 42% Ni). The tab portion 303A is connected to the lead frame via a tab suspension lead 303D shown in FIG. 46 before the lead frame cutting step. The tab portion 303A has a rectangular shape corresponding to the planar shape of the semiconductor chip 302, and the tab suspension lead 303D has a tab portion 303A.
Are supported so as to extend in the same direction as the long side direction of the tab portion 303A.

A plurality of one ends of the inner lead 303B are arranged around the short side of the tab 303A of the lead 303. The other end of the inner lead 303B is integrally formed with and electrically connected to the outer lead 303C. The functions of the outer leads 303C are defined as shown in FIG. In other words, I / O1 to I / O4 are the outer leads 303C for input / output signals.
(Pin). ▲ ▼ indicates an outer lead 303C for a write enable signal. ▲ ▼ indicates an outer lead 303C for a row address strobe signal. A _{0 to} A ₈
Is an outer lead 303C for an address signal. OE is an outer lead 303C for an output enable signal. ▲ ▼ indicates an outer lead 303C for a column address strobe signal. V _cc is the power supply voltage (for example, 5
[V]) outer lead 303C. V _ss is an outer lead 303C for a reference voltage (for example, 0 [V]).

The covering wire 305 is, as shown in FIG.
Is covered with an insulator 305B. Metal wire
305A uses gold (Au) in this embodiment. Further, the metal wire 305A may be formed of copper (Cu), aluminum (Al), or the like as a material other than the above. In this embodiment, a polyurethane resin or a polyimide resin is used for the insulator 305B. Further, the insulator 305B may be formed of a resin material such as an ester imide resin or an ester amide resin as a material other than the above.

The covering wire 305 is connected to the external terminal 302E by a ball & wedge bonding method or a wedge & wedge bonding method. That is, the semiconductor chip 30
The second external terminal 302E end metal balls 305A ₁ insulator 305B is formed of a metal wire 305A exposed melted removal (wire feed side of the distal end portion of) the coated wire 305 is connected. Metal ball 305A ₁ is the metal wire 305A of the covering wire 305
For example, it is configured to have a diameter that is about two to three times larger than the diameter. Metal ball 305 of insulated wire 305
A ₁ is connected to the external terminal 302E by combining ultrasonic vibration to thermocompression or thermocompression (first bonding).

The inner wire 303B of the lead 303 has a covered wire 305
The other end portion of the connecting metal lines 305A ₂ exposed by breaking the insulator 305B of the connecting portion (the supply side rear portion of the opposite side of the wire). At the other end of the covered wire 305, substantially only the insulator 305B at the connection portion with the inner lead 303B is removed, and the other insulator 305B remains. Breaking of the insulator 305B at the other end of the covered wire 305 and connection with the inner lead 303B are performed by using ultrasonic vibration in combination with thermocompression bonding using bonding technology or thermocompression bonding using wedge bonding technology (second bonding). .

As described above, in the resin-encapsulated semiconductor device 301 using the covered wire 305, since the surface of the metal wire 305A is covered with the insulator 305B, between the covered wires 305, the covered wire 305 and the semiconductor chip 302, the tab portion Short circuit with each of 303A and inner lead 303B can be prevented. As a result, the electrical reliability of the resin-sealed semiconductor device 301 can be improved.

In addition, the resin-encapsulated semiconductor device 301 that uses the covered wire 305
Metal ball 305A formed by metal wire 305A at one end of 305 ₁
The metal wire 305A which is exposed by breaking the insulator 305B at the connection portion at the other end of the covered wire 305 to the inner lead 303B.
By connecting ₂ , the size of the metal ball 305A ₁ is large, so that the contact area between the metal ball 305A ₁ and the external terminal 302E can be increased, bondability between the two can be improved, and the inner lead 303B and The other end of the covered wire 305 other than the part to be connected is covered with the insulator 305B, and a short circuit caused by contact between the other end of the covered wire 305 and the other end of the adjacent covered wire 305 can be prevented. Therefore, it is possible to reduce the interval between the inner leads 303B and increase the number of pins (multiple pins).

The semiconductor chip 302, tab portion 303A, inner lead 3
03B and the covering wire 305 are sealed with a resin material (for example, epoxy resin material) 306. The resin material 306 is formed by injecting and solidifying the resin material in the area defined by the mold (in the area corresponding to the outer peripheral shape of the resin material 306) from the direction of arrow G shown in FIG. 46. . The resin injection port (gate) of the mold is provided on the tab suspension lead 303D side on the right side in FIG.

The shape of the lead frame used in the resin-encapsulated semiconductor device 301, that is, the tab portion 303A, the inner lead 303B,
Each shape of the outer lead 303C and the tab suspension lead 303D is formed by punching. The lead frame formed by punching in this way is shown by a dotted line in FIG.
The surface on which the burrs formed at the corners of the respective ends in the punching protrude is used on the lower side, and the surface on the corners of the respective ends formed by the punching where the burrs occur is used on the upper side. In other words, the semiconductor chip 302 is mounted on the surface of the tab portion 303A where the corner has been drooped by the punching, and the covering wire 305 is connected to the surface of the inner lead 303B where the corner has drooped in the punching. I have. The portions where the corners of the lead 303 are drooped are just chamfered, and the shape of the sharp corners is relaxed.

When the burrs at the respective corners of the lead 303 are used, as shown in FIG. 47 (enlarged sectional view of the main part), the tab 303A and the covering wire 305 of the resin-encapsulated semiconductor device 301 are short-circuited. I do. That is, the thin insulator 305B (about 1.0 μm in this embodiment) of the covered wire 305 is damaged by the concentration of stress by the burr based on the contraction stress of the resin material 306, and the burr at the corner of the tab 303A. And the metal wire 305A of the covering wire 305 is short-circuited.

FIG. 51 (a diagram showing the short-circuit rate between the tab and the wire) shows the short-circuit rate [%] between the tab portion 303A and the covered wire 305 with respect to the temperature cycle. As shown in FIG. 51, in the case where burrs are formed on each corner of the lead 303, the short-circuit rate increases as the temperature cycle increases. On the other hand, in the case where the surface of each of the leads 303 having a droop at each corner is used, the short circuit hardly occurs even if the temperature cycle increases.

When the burrs at the corners of the leads 303 are used, as shown in FIG. 48 (enlarged cross-sectional view of a main part), the covering wire 305 of the resin-sealed semiconductor device 301 is broken. The disconnection of the covered wire 305 occurs because the burrs concentrate the stress based on the contraction stress of the resin material 306, as described above.

FIG. 52 (a diagram showing the breaking rate of the wire) shows the breaking rate [%] of the covered wire 305 with respect to the temperature cycle. As shown in FIG. 52, in the case where burrs are formed on each corner of the lead 303, the disconnection rate increases as the temperature cycle increases. On the other hand, in the case where the surface of each of the leads 303 where the corners are formed is used, the disconnection hardly occurs even if the temperature cycle increases.

Thus, the semiconductor chip mounted on the tab 303A
The external terminal 302E of 302 and the inner lead 303B are connected by a covering wire 305, and the covering wire 305 and the covering wire 30
In the resin-encapsulated semiconductor device 301 in which the connection portion 5 is covered with the resin material 306, at least the shape of the corner of the tab 303A or the corner of the inner lead 303B in the portion where the covering wire 305 extends is relaxed. By doing so, the concentration of the stress based on the shrinkage of the resin material 306 on the portion of the covering wire 305 that is in contact with the corner of the tab portion 303A or the corner of the inner lead 303B is reduced. Tab part 303A
And the covering wire 305 can be prevented from being short-circuited to the metal wire 305A, or the covering wire 305 can be prevented from breaking. As a result, the electrical reliability of the resin-sealed semiconductor device 301 can be improved.

Further, as shown in FIGS. 49 and 50 (enlarged sectional view of a main part), the resin-encapsulated semiconductor device 301 has an insulating property even when the covering wire 305 is in contact with the corner of the end of the semiconductor chip 302. Since the breakage of the covering wire 305 or the breakage of the covering wire 305 occurs, the shape of the corner of the semiconductor chip 302 where the covering wire 305 extends is reduced. In other words, the resin-encapsulated semiconductor device 301 is formed by chamfering the corner of the end of the semiconductor chip 302, specifically, the corner of the scribe area around the semiconductor chip 302, thereby forming the insulator 305B of the covered wire 305.
This is configured to prevent damage to the wire or disconnection of the covered wire 305.

Further, as shown in FIG. 45, the covered wire 305
The trajectory may be controlled so as not to contact the corner of the semiconductor chip 302, the corner of the tab 303A, or the corner of the inner lead 303B, that is, the portion where the burr projects. This covered wire 305
Is controlled by the arrangement position of the external terminal 302E of the semiconductor chip 302, the height of the covering wire 305 on the external terminal 302E, the connection position between the inner lead 303B and the covering wire 305, and the like.

As described above, in the resin-encapsulated semiconductor device 301, the trajectory is controlled so that the covering wire 305 does not contact the corner of the semiconductor chip 302, the corner of the tab 303A, or the corner of the inner lead 303B. , The coated wire 30
Since the stress due to the shrinkage of the resin material 306 does not concentrate on 5, the semiconductor chip 302 or the tab 303A due to the damage of the insulator 306B.
And the covering wire 305 can be prevented from being short-circuited to the metal wire 305A, or the covering wire 305 can be prevented from breaking. As a result, the electrical reliability of the resin-sealed semiconductor device 301 can be improved. Originally, even if the covered wire 305 is brought into contact with each of the semiconductor chip 302 and the tab portion 303A, a short circuit should not occur, but as described above, the insulator 305B of the covered wire 305 or the broken wire 305 occurs. Therefore, in order to prevent such a defect, the present invention sets the covering wire 30 so as to be actively separated from the corner of the semiconductor chip 302 and the corner of the tab 303A.
5 trajectories are controlled.

When the surface of the lead 303 from which the burrs protrude is used as shown in FIG. 53 (enlarged cross-sectional view of the main part), the sharp shape of the burr is used as shown in FIG. 54 (enlarged cross-sectional view of the main part). Relieve (beveling). The relief of the shape can be formed, for example, by forming a lead frame by punching and then pressing the lead frame.

The present invention can be similarly applied to a case where a lead frame is formed by etching. That is, according to the present invention, the shape of each corner of the lead frame formed by etching is relaxed.

Further, in the present invention, each corner of the lead frame may be provided with a shape relaxing member for relaxing the shape of that portion. The shape relaxing member is formed of, for example, an Ag or Au plating layer or a resin film.

Embodiment II of Embodiment 3 is another embodiment of the present invention in which the development cost of the resin-encapsulated semiconductor device is reduced.

FIGS. 55 and 56 (schematic plan views showing respective forming steps) show a method of forming a resin-sealed semiconductor device which is II of Example 3 of the present invention.

The resin-encapsulated semiconductor device of II of the third embodiment is formed as follows.

First, as shown in FIG. 55, the semiconductor chip 302 is mounted on the tab 303A, and the external terminals 302E of the semiconductor chip 302 are mounted.
And the inner lead 303B are connected with the covering wire 305.
Then, by sealing the semiconductor chip 302 and the like with the resin material 306, a resin-sealed semiconductor device 301 is formed. That is, the resin-sealed semiconductor device 301 seals the semiconductor chip 302 with the first package (including the lead 303 and the resin material 306).

Next, although it is desired to use the same semiconductor chip 302 (having the same function), the semiconductor chip 302 differs from the first package in the case where the arrangement of the board for mounting the resin-sealed semiconductor device 1 and the terminal arrangement of the external device are different. Develop and prepare a second package having the arrangement of the leads 303 according to the terminal arrangement of the board and the external device. Then, as shown in FIG. 56, the resin-encapsulated semiconductor device 30 is placed on the tab portion 303A of the second package.
The same semiconductor chip 302 as that of No. 1 is mounted, and the external terminals 302E of the semiconductor chip 302 and the inner leads 303B are connected by the covering wire 305. The covered wire 305 can be freely bonded even if it comes into contact with another adjacent covered wire 305 or crosses the inner lead 303B or the tab suspension lead 303D because it is not short-circuited therewith. Then, by sealing the semiconductor chip 302 and the like with the resin material 306, a resin-sealed semiconductor device 301A can be formed. In this resin-sealed semiconductor device 301A, the same semiconductor chip 302 as that of the resin-sealed semiconductor device 301 is sealed in a second package different from the first package.

As described above, the method for forming the resin-sealed semiconductor device 301 using the covering wire 305 includes mounting the semiconductor chip 302 on the tab portion 303A (chip mounting position) of the first package, The terminal 302 </ b> E and the inner lead 303 </ b> B are connected by a covering wire 305 to form a first resin-sealed semiconductor device 301, and a second resin of a different type from the first package of the first resin-sealed semiconductor device 301. The first resin-encapsulated semiconductor device 30 is attached to the tab portion 303A of the package.
The same semiconductor chip 302 as the first semiconductor chip 302 is mounted, and an external terminal 302E of the semiconductor chip 302 and an inner lead 303B are connected by a covering wire 305 to form a second resin-sealed semiconductor device 301.
By forming A, the external terminal 302E of the semiconductor chip 302 and the inner lead 303B are connected with the covering wire 305 across the other inner lead 303B, or the covering wire 305
Can be crossed to connect the external terminals 302E of the semiconductor chip 302 and the inner leads 303B, so that the same semiconductor chip 302 is used (standardization of the semiconductor chip 302) and a plurality of types using different types of packages are used. Resin-sealed semiconductor devices 301 and 301A can be formed. As a result, since the development cost of the package is lower than the development cost of the semiconductor chip 302, various types of resin-sealed semiconductor devices 301 and 301A can be formed at a low development cost. For example, the present invention uses a single semiconductor chip 302 to provide a pin-insertion type such as a DIP type or a ZIP type, or a surface-mount type resin-sealed type semiconductor such as a SOJ type, SOP type, QFP type or PLCC type. The device 301 can be formed at a low development cost.

The resin-encapsulated semiconductor device of Example III of the second embodiment is formed as follows.

First, as shown in FIG. 55, the tab 303A of the lead 303
The semiconductor chip 302 is mounted thereon, and the external terminals 302E of the semiconductor chip 302 and the inner leads 303B are covered with wires 305.
Connect with. The tab portion 303A is configured to be slightly larger than a normal tab size, and a plurality of types of semiconductor chips 30 are provided.
It is configured so that 2 can be mounted. Then, by sealing the semiconductor chip 302 and the like with the resin material 306, a resin-sealed semiconductor device 301 is formed. That is, in the resin-sealed semiconductor device 301, the first semiconductor chip 302 is mounted on the tab 303A of the lead 303, and this is sealed with the resin material 306.

Next, the same lead (lead frame) 303 as that of the resin-encapsulated semiconductor device 301 is used, and as shown in FIG. 56, a semiconductor chip of a different type from the semiconductor chip 302 is provided on the tab portion 303A. A semiconductor chip 302 (for example, a semiconductor chip having a different function and the same function but different arrangement of the external terminals 302E) is mounted, and the external terminals 302E of the semiconductor chip 302 'and the inner leads 303B are connected by a covering wire 305. Insulated wire 3
05 can be freely bonded because it does not short-circuit with the other covered wire 305 even if it comes into contact with the covered wire 305 or crosses the inner lead 303B or the tab suspension lead 303D. Then, the semiconductor chip 302 ′ and the like are sealed with a resin material 306, thereby forming a resin-sealed semiconductor device 301.
A can be formed. This resin-encapsulated semiconductor device 3
01A is the same lead 303 as the resin-sealed semiconductor device 301
A semiconductor chip 302 ′ of a type different from that of the semiconductor chip 302 is mounted on the tab portion 303 A, and this is sealed with a resin material 306.

As described above, the method of forming the resin-encapsulated semiconductor device 301 using the covered wire 305 includes the tab portion 30 of the lead 303.
After mounting the first semiconductor chip 302 on 3A (chip mounting position) and connecting the external terminals 302E of the first semiconductor chip 302 and the inner leads 303B with the covering wires 305, the resin material 3
06 to form a first resin-sealed semiconductor device 301, and the first resin-sealed semiconductor device 301 is attached to the same tab portion 303 A of the lead 303 as the first resin-sealed semiconductor device 301. Device 3
01 is mounted with a second semiconductor chip 302 ′ of a different type from the first semiconductor chip 302, and the external terminals 302 E of the second semiconductor chip 302 ′ and the inner leads 303 B are connected with a covering wire 305 and then sealed with a resin material 306. By stopping and forming the second resin-sealed semiconductor device 301A, other inner leads can be formed.
The external terminal 302E of the semiconductor chip 302 'is connected to the inner lead 303B with the covering wire 305 across the 303B, or the outer terminal of the semiconductor chip 302' is
Since the same lead (lead frame) 303 is used (standardization of the lead frame) and different types of semiconductor chips can be connected because the 302E and the inner lead 303B can be connected.
Multiple types of resin-encapsulated semiconductor devices 3 using 302, 302 '
01, 301A can be formed. As a result, it is not necessary to develop the leads 303 for each development of the semiconductor chips 302 and 302 ', so that various types of resin-sealed semiconductor devices 301 and 301A can be formed at a low development cost. For example, the present invention relates to a DIP-type resin-sealed semiconductor device 3
Instead of the semiconductor chip 302 mounted on 01, the semiconductor chip 302 ′ mounted on the SOJ-type resin-encapsulated semiconductor device 301
(E.g., having the same recording capability and the same number of external terminals 302E, but different locations of the external terminals 302E) are mounted on the DIP-type resin-sealed semiconductor device 301, and the semiconductor chip 302 '
Can be formed to mount the DIP-type resin-sealed semiconductor device 301A.

Although the invention made by the inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment and can be variously modified without departing from the gist thereof. Of course.

For example, according to the present invention, a plurality of semiconductor chips are mounted on the surface of a wiring board, and each terminal of the wiring board is connected to an external terminal of the semiconductor chip by a covering wire using a ball & wedge bonding method or a wedge & wedge bonding method. The present invention can be applied to a semiconductor device in which a covering wire and a connection portion thereof are covered with at least a resin. The resin used in the semiconductor device is, for example, a polyimide resin, and is applied by a potting technique.

Further, the present invention is applied to a ceramic-sealed semiconductor device in which external terminals of a semiconductor chip and leads are connected with a covering wire, the covering wire and its connection portion are covered at least with a resin, and these are sealed with a ceramic material. can do.

The following is a brief description of an effect obtained by the representative one of the inventions disclosed in the present embodiment.

In a semiconductor device using a covered wire, damage to the insulator of the covered wire and disconnection of the covered wire can be prevented, and electrical reliability can be improved.

Further, in a semiconductor device using a covered wire, the development cost of a multi-package semiconductor device having the same function can be reduced.

Further, in a semiconductor device using a covered wire, the development cost of a plurality of types of semiconductor devices on which semiconductor chips having different functions are mounted can be reduced.

(4) Embodiment 4 This embodiment is a detail or a modified example of the peripheral chamfering on the chip main surface shown in the previous embodiment 3 and is different from the preceding other embodiments and the embodiments described later. It forms part of the semiconductor integrated circuit device shown.

 This embodiment will be described with reference to FIGS. 57 to 60.

FIG. 57 is a cross-sectional view of the wafer after the dicing step by the semi-full cut method is completed. In the figure,
Reference numeral 401 denotes a cutting groove formed by a main blade, 402 denotes a bevel portion formed by a chamfer blade, 403 denotes a device main surface of a pellet, 404 denotes an Si wafer substrate, 405 denotes an uncut portion, 406 denotes an adhesive layer, and 407 denotes a resin seed.

As for the dimensions of each part, a is 5 to 20 μm, b is 5 to 20 μm,
c is 20-100 μm, d is 200-400 μm, e is 5-20 μm
m and θ are 20 ° to 45 °.

FIG. 58 is a partial schematic cross-sectional view showing a process of bevel chamfer dicing. In the figure, 401a is a primary vertical cutting groove by a main blade, 401b is a vertical cutting groove after further bevel cutting, and 402 is a chamfering blade (sub-blade).
404 is an uncut portion, 406 is an adhesive layer, 407 is a sheet, 408a is a main spindle, 408b is a sub spindle, 409a is a main rotary blade, 40
9b is an auxiliary rotating blade.

FIG. 59 is a cross-sectional view showing a state where a wafer is attached to a frame via a resin sheet during dicing. In the figure
404 is a Si wafer bonded with its main surface facing up, 4
Reference numeral 07 denotes a resin sheet having an adhesive layer formed on the upper surface, and reference numeral 410 denotes an annular metal or resin (hard) frame.

FIG. 60 is a top view showing a device main surface of a wafer.
In the figure, 404 is a Si wafer, 411 is an orientation flat, A1 to 5 are vertical scribe lines to be cut by blades, that is, avenues, and S1 to 7 are similar horizontal scribe lines, that is, streets. .

Hereinafter, dicing according to the present invention. Process 57-60
Description will be made based on the drawings.

As shown in FIG. 59, the wafer 40 after the electrical test (wafer test by a prober) at the wafer stage is completed.
4 is a frame body with the device side up, via the adhesive sheet 407
Fixed to 410.

Next, the lower surface is fixed to the dicer (eg, Disco Dual Dicer DFD-3D /
8) Adsorb and fix on the adsorption stage. Further, in this state, as shown in FIG. 60, cutting is performed by each avenue sequentially rotating blades, and then the stage is rotated by 90 degrees, and each stred is similarly cut by the rotating blades. At this time, as shown in FIG. 58, the main blade 409a and the sub-blade
409b performs the cutting with a shift of one block, and the sub-blade follows the main blade. In cutting, a so-called semi-full cut method is used to provide a rest of about several μm.

The cut wafer is transferred to a die bonding process while being fixed to the frame 410. In die bonding, the target chip is placed on the sheet
The suction collet lifted up from below and approached from above is transferred onto the die pad of the lead frame and die-bonded.

(5) Fifth Embodiment This embodiment describes the details of some of the steps of each of the above embodiments or a bonding process which is a modification thereof.

FIG. 61 is a schematic partial sectional view showing a main part of the coated wire bonding apparatus of the present invention. In the same figure, reference numeral 501 denotes a ball having a diameter of about 70 to 90 μm formed by a separated arc discharge, reference numeral 502 denotes a coating removal portion (20 to 200 μm) in which the resin coating melts due to heat during ball formation, and reference numeral 503 denotes a ball forming atmosphere. A supply gas nozzle, 504 is a discharge electrode integrated therewith, 505a is a core material of a bonding wire, that is, a metal core portion, 505b is a coating layer thereof, and 506 is a thermosonic ball bonding (ball Wedge
Type) capillary (bonding tool)
In addition to applying pressure in the vertical direction, ultrasonic vibration can be applied in the horizontal direction (the extending direction of the bonding arm). 507a and 507b are melt-up preventing gas nozzles, 508 is a multiple lead frame, and 509a to 509f are die pads on the die pad on the lead frame, respectively.
Bonded integrated circuit chip (509a is wire-bonded), 510 is a heat block for heating the leads and the chip, 511 is a double-sided opening tube through which the lead frame is passed, 512
Is an opening for wire bonding provided on the upper side thereof, 521 is a gas flow for preventing melting, 522 is a ball forming atmosphere gas for shielding the ball portion during ball formation and subsequent annealing, and 523a to d are lead frames. The lead gas atmosphere flow for preventing oxidation, etc., 524 is the transfer direction of the lead frame.

Tables 5 and 6 show various conditions for bonding in FIG.

The specific process of wire bonding is as follows.
Explanation will be made based on the figures and Tables 5 and 6.

First, with the end of the wire on the spool side grounded, applying a pulse voltage so that the wire side becomes a positive electrode while keeping the distance between the tip of the wire and the discharge electrode 504 constant, thereby making the wire tip An arc is generated between the electrode and the electrode 504, and the heat forms the ball 501 and melts the coating at the tip. At this time, a ball atmosphere gas 522 is blown from the side of the wire before and after formation of the ball to prevent oxidation of the ball. On the other hand, at the same time, in order to prevent excessive melting of the coating, a cooling gas 521 is supplied to the wire neck portion immediately above the ball from above while the ball is being formed and until the melting of the coating is stopped.

The ball, which has been cooled to about 300 to 200 ° C. in the ball forming gas 522 from the ball temperature (1000 ° C. or higher) at the time of discharge, is subjected to wire bonding. When ball formation is completed, the electrode
504 is retracted, the capillary 506 descends, enters the tube 511 through the opening 512 of the tube 511, and performs the first bonding (on the chip 509b by thermosonic bonding).
Then, the capillary 506 is moved while sending the wire 505 to the second bonding point of the corresponding lead. At that point, the wet bonding is performed while breaking the coating. During this time, the inside of the tube is filled with a lead atmosphere gas.

The bonding cycle of one wire above is 0.1
This is performed for about 0.3 seconds. By repeating the above cycle, bonding of all the wires is performed.

(6) Sixth Embodiment This embodiment shows details or modifications of a part of the structure or steps of the preceding embodiment.

FIG. 62 is a partial sectional view of the surface mount resin package of the present invention. In the figure, 602a is a Si substrate (200 to 400μ).
602b is a final passivation film (1 μm thick) made of SiO ₂ , 602c is an Al bonding pad (1 μm thick; 100 μm × 100 μm square), 602d and e are interlayer insulating films made of PSG or the like (0.5 to 1.5) μm thickness), 602f is LOCOS
Field SiO ₂ film (0.3-1 μm thick) by oxidation (selective oxidation by SiN), 603a-c are lead frames patterned from one metal sheet, of which 603a is a die pad portion and 603b is an inner The lead portion, 603c, is an outer lead portion. 604 is an adhesive layer for die bonding such as Ag paste, 605a is a bonding wire core material, 605b is its coating, 606 is the low stress resin material shown in the previous embodiment, 607 is a spot plating portion at the inner end of the lead. Reference numeral 608 denotes a chamfered portion at the tip end.

Table 7 is a list showing materials of respective parts of specific examples of these resin-sealed devices, and the examples correspond to Tables 5 and 6.

〔The invention's effect〕

According to the present invention, a device in which a lead and a pad on a chip are wire-bonded with a coated wire is transfer-molded with a resin composition containing a large amount of a release agent, so that heat resistance is good and workability is improved. Semiconductor device with good performance.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a resin-encapsulated semiconductor device which is I of Embodiment 1 of the present invention, FIG. 2 is a schematic enlarged sectional view of a wire bonding portion, and FIG. FIG. 4 is a schematic perspective view of a main part of the wire bonding apparatus, FIG. 5 is a partial sectional view showing a specific configuration of a main part of the wire bonding apparatus, and FIG. 6 is an arrow in FIG. FIG. 7 is a plan view seen from the direction VI, FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG. 6, FIG. 8 is a schematic diagram showing the principle of forming metal balls, and FIG. FIG. 10 is an enlarged perspective view of a main part of the spool, FIG. 11 is a schematic plan view of a local heating unit for wire bonding, and FIG. 12 is a plan view showing an example of the wire bonding. FIG. 13 is a diagram showing the state of the coated wire tip touching. FIG. 14 is an enlarged partial sectional view showing the chip short state, FIG. 15 is a partial sectional view showing the tab touch state of the coated wire, FIG. 16 is an enlarged partial sectional view showing the tab short state, FIG. FIG. 18 is a diagram showing the short-circuit rate between the semiconductor chip and the coated wire with respect to the temperature cycle in the present invention. FIG. 18 is a diagram showing the short-circuit rate between the tab and the coated wire with respect to the temperature cycle in the present invention. FIG. 20 is a model diagram showing the experimental conditions used for evaluating the coating film of the coating wire used in FIG. 20, FIG. 20 and FIG. 21 are diagrams showing the results of a comparative experiment of the wear strength of the coating film in the present invention, respectively. FIG. 22 is a diagram showing experimental results on the relationship between temperature and deterioration rate in the present invention. FIG. 23 is a graph showing imidization rate (horizontal axis), deterioration rate, ie, deterioration rate (left vertical axis), Wire Seca Fig. 24 shows the experimental results on the relationship between the peel strength of the (2nd) bonding (vertical axis on the right), Fig. 24 shows the experimental results on the temperature cycle amplitude and temperature cycle life of the coated wire, Fig. 25 FIG. 26 is a diagram showing the effect of the presence or absence of a coloring agent on the coating film of a coated wire on the deterioration rate (deterioration rate). FIG. 26 to FIG. 30 are embodiments 1 of a wire bonding method usable in the present invention. 31 is a partial cross-sectional view of the wire bonding part showing II to VI, and FIG. 31 is a partial cross-sectional view of the wire bonding part showing the composite coating film structure according to VII of Embodiment 1 of the present invention. FIG. 32 is a cross-sectional view showing the structure of a semiconductor device which is Embodiment 2 of the present invention. FIG. 33 is a plan view showing a main part of a lead frame used in the above embodiment. FIG. FIG. 35 is a perspective view showing a wire used in the above embodiment, FIG. 36 is an explanatory diagram showing characteristics of the above wire, and FIG. 37 is an embodiment of the above example. 38 (a) and 38 (b) are explanatory views showing an apparatus configuration of a wire bonding apparatus used in the above embodiment. 39 is an explanatory diagram showing the configuration of a resin molding device used for forming the package of the above embodiment, FIG. 40 is a plan view showing a mold surface in the resin molding device, and FIG. 41 is a diagram showing the coefficient of thermal expansion and filler. Explanatory diagram showing the relationship with the compounding amount, FIG. 42 FIG. 43 is an explanatory diagram showing the relationship between the resin viscosity in the molten state and the blending amount of the filler, FIG. 43 is an explanatory diagram showing the relationship between the occurrence rate of wire short-circuit and the blending amount of the filler in comparison with the prior art, FIG. The figure is an explanatory diagram showing the change in the immersion state of water in PCT (pressure cooker test) in comparison with the conventional technology. FIG. 45 is a fragmentary cross-sectional view showing a configuration of a DIP-type resin-encapsulated semiconductor device which is I of Embodiment 3 of the present invention. FIG. 46 is a partial cross-sectional plan view of the resin-encapsulated semiconductor device. FIGS. 47 to 50 are enlarged cross-sectional views of main parts of the resin-encapsulated semiconductor device. FIG. 51 is a diagram showing a short-circuit rate between a tab and a wire of the resin-encapsulated semiconductor device. FIG. 52 is a diagram showing a wire breakage rate of the resin-encapsulated semiconductor device. FIGS. 53 and 54 are main portions showing a method of forming leads of the resin-encapsulated semiconductor device for each forming step. FIG. 55 and FIG. 56 are schematic plan views showing a method for forming a resin-sealed semiconductor device, which is II of Example 3 of the present invention, for each forming step. FIG. 57 is a cross-sectional view of a main part of a wafer showing bevel dicing according to Example 4 of the present invention. FIG. 58 is an explanatory diagram of the entire structure. FIG. 59 is a view showing an annular frame used for dicing. FIG. 60 is a cross-sectional view showing a state where the wafer is stuck via an adhesive sheet. FIG. 60 is a top view of the wafer showing a state of a scribe line for pelletizing the wafer. FIG. 61 is a schematic partial cross-sectional view showing details of a bonding process according to Example 5 of the present invention. FIG. 62 is a sectional view of a surface mount device according to Example 6 of the present invention. 1 ... semiconductor device, 2 ... semiconductor chip, 2A ... substrate,
2B: Passivation film, 2C: External terminal (bonding pad), 3: Lead, 3A: Tab, 3B: Inner lead, 4: Bonding material, 5: Coated wire, 5A:
Metal wire, 5A ₁ … Metal ball, 5A ₁₁ , 5A ₁₂ … First bonding part, 5A ₂ , 5A ₂₂ … Second bonding part, 5B, 5Ba… Coating film, 5C… Second coating film , 6 ...
Resin material, 10 Bonding device body, 11 Spool, 11A Connection terminal, 11Aa Insulator, 11Ab Conductor, 11Ac Connection metal part, 12 Bonding part, 13
…… Tensioner, 14… Wire guide member, 15… Wire clamper, 16… Bonding tool (capillary),
16A bonding arm, 17 support base (table for mounting semiconductor device), 18A coating member, 18B tool insertion port, 18C fluid spray nozzle, 18D electric torch (arc electrode), 18E …… Suction tube, 18F …… Nipping member, 18
G: Support member, 18H: Insulation member, 18I: Crank shaft, 18J: Shaft, 18K: Drive source, 19: Suction device, 20: Arc generator, 21: Spool holder, 21
A: rotating shaft, 22: bonding head (digital bonding head), 22A: guide member, 22B: arm moving member, 22C: female screw member, 22D: male screw member,
22E ... motor, 22F ... rotary shaft, 22G ... elastic member, 23
... XY table, 24 ... Base, 25 ... Fluid spraying device (fluid source), 25A ... Cooling device, 25B ... Flow meter, 25C ... Fluid transfer pipe, 25D ... Insulation material, 26 ... Heater, 26A: Feeding line, C _1: Capacitor, C _2: Storage capacitor, D:
… Arc thyristor, R… resistance, D, C… DC power supply, GND… reference potential, V voltmeter, A… ammeter.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Kaneda 5-22-1, Kamizuhoncho, Kodaira-shi, Tokyo Inside Hitachi Microcomputer Engineering Co., Ltd. (72) Inventor Shunji Koike Kamimizuhoncho, Kodaira-shi 5-22-1, Hitachi Microcomputer Engineering Co., Ltd. (72) Inventor Hiroshi Watanabe 5-20-1, Josuihoncho, Kodaira-shi, Tokyo Inside Musashi Plant of Hitachi, Ltd. (72) Inventor Sei Honma Tokyo 1-5-1, Marunouchi, Chiyoda-ku, Tokyo Hitachi, Ltd. (56) References JP-A-63-266842 (JP, A) JP-A-63-58849 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) H01L 21/60 301 H01L 21/607 H01L 21/56

Claims (22)

(57) [Claims] 1. A method for manufacturing a semiconductor device, comprising connecting a lead to an external terminal of a semiconductor chip by a covered wire in which a surface of a metal wire is covered with an insulating covering film. The film is made of a heat-resistant polyurethane containing a structural unit derived from terephthalic acid in a molecular skeleton by reacting a polyol component and an isocyanate, and one end of the coated wire is connected to the external terminal of a semiconductor chip.
A method for manufacturing a semiconductor device, comprising connecting the other end to a lead. 2. The semiconductor according to claim 1, wherein said coating film on said one end side of said coating wire is removed when forming a metal ball, and said metal ball is connected to said external terminal of said semiconductor chip. Device manufacturing method. 3. The method of manufacturing a semiconductor device according to claim 1, wherein said one end side of said covering wire is connected to said external terminal of said semiconductor chip by using both ultrasonic vibration and thermocompression bonding. 4. The method according to claim 1, wherein the other end of the coated wire is brought into contact with the lead to break a coating film at the contact portion, and the metal wire on the other end of the coated wire is connected to the lead. The method for manufacturing a semiconductor device according to claim 1, wherein: 5. The method of manufacturing a semiconductor device according to claim 1, wherein the coating film on the other end is removed before connecting the other end of the coating wire to the lead. . 6. The method according to claim 1, wherein when the other end of the covered wire is connected to the lead, a wire bonding portion of the lead is particularly locally heated.
The manufacturing method of the semiconductor device described in the above. 7. The method of manufacturing a semiconductor device according to claim 1, wherein a predetermined amount of a coloring agent is added to said coating of said coating wire. 8. The method according to claim 1, wherein a second insulating coating film is provided on the coating film of the coating wire. 9. A method of manufacturing a semiconductor device, comprising connecting an external terminal of a semiconductor chip and a lead by a covered wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering of the covered wire is performed. The coating film is made of a non-carbonized material with a deterioration rate of 20% or less in reducing the number of coating film breakage after 100 hours at 150 ° C. to 175 ° C., and when forming metal balls or removing the coating film. A method for manufacturing a semiconductor device, comprising: 10. A semiconductor device in which external terminals of a semiconductor chip and leads are connected by a covering wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covering wire is A semiconductor device comprising a heat-resistant polyurethane containing a structural unit derived from terephthalic acid in a molecular skeleton by reacting a polyol component with an isocyanate. 11. A semiconductor device in which an external terminal of a semiconductor chip and a lead are connected by a covering wire in which a surface of a metal wire is covered with an insulating covering film, wherein the covering film of the covering wire is provided. Degradation rate in reducing the number of times of coating film destruction after 150 hours to 150 ° C to 175 ° C for 100 hours is within 20%, and it is made of non-carbonized material when forming metal balls or removing the coating film. Semiconductor device. 12. A resin-encapsulated semiconductor device in which external terminals formed on a semiconductor chip and leads led out of the package are connected by a metal wire, and the periphery thereof is molded with a resin composition. Between the metal wire and the resin composition, there is provided an intermediate layer formed of an insulating resin made of polyurethane containing a structural unit derived from terephthalic acid in a molecular skeleton by reacting a polyol component and an isocyanate. A resin-encapsulated semiconductor device, wherein the coefficient of thermal expansion of the resin composition is controlled to 10 × 10 ⁻⁶ / ° C. or less. 13. An external terminal formed on a semiconductor chip and a lead led out of the package are connected by a metal wire having an intermediate layer made of an insulating resin around the external terminal, and the periphery is further connected to a resin composition. A resin-encapsulated semiconductor device molded with a total diameter of the metal wire and the intermediate layer of 30μ
m, and the coefficient of thermal expansion of the resin composition is controlled to 10 × 10 ⁻⁶ / ° C. or less. 14. The above-mentioned metal is made of (Au), and the intermediate layer is formed of an insulating resin made of polyurethane containing a structural unit derived from terephthalic acid in a molecular skeleton by reacting a polyol component with isocyanate. 14. The resin-sealed semiconductor device according to claim 13, wherein: 15. A metal wire for connecting an external terminal and a lead formed on a semiconductor chip to a first intermediate layer formed of an insulating resin around the metal wire, and a releasable metal formed around the first intermediate layer. A resin-encapsulated semiconductor device comprising: a second intermediate layer on which a good resin is formed. 16. The second intermediate layer is formed by forming a first intermediate layer made of a heat-resistant polyurethane resin around the metal wire and then applying a fluororesin or a silicone resin. 16. The resin-encapsulated semiconductor device according to claim 15, wherein: 17. An intermediate layer is formed by reacting a polyol component and an isocyanate around a metal wire and applying an insulating resin made of polyurethane containing a structural unit derived from terephthalic acid to a molecular skeleton to form an intermediate layer. After connecting the external terminals and leads of the semiconductor chip with metal wires,
A method of manufacturing a resin-encapsulated semiconductor device, comprising molding with a resin composition having a coefficient of thermal expansion controlled to 10 × 10 ⁻⁶ / ° C. or less for the connection range. 18. An intermediate layer made of an insulating resin is formed around a metal wire to obtain a wire, and the wire is used to connect a semiconductor chip mounted on a lead frame to a lead. The frame is placed in a mold having a plurality of cavities formed therein, and molten resin is injected into the plurality of cavities of the mold from at least two or more resin sources at a high pressure to form a package. A method of manufacturing a resin-sealed semiconductor device. 19. The resin supply source is a plurality of pots connected to a transfer cylinder. After a tablet made of a resin composition is charged into each of the plurality of pots, a plunger provided in each pot is opened. 19. The method for manufacturing a resin-encapsulated semiconductor device according to claim 18, wherein the high-pressure injection of the molten resin is performed into each of the cavities by pressing in synchronization. 20. An intermediate layer forming apparatus for forming first and second intermediate layers around a metal wire, comprising a first storage tank and a second storage tank which are continuously arranged, Each storage tank has a pulley rotatable in a vertical plane, and the lowermost part of the pulley is immersed in the stored liquid, and a predetermined amount of storage pumped by the pulley at the uppermost part of the pulley. An intermediate layer forming apparatus, wherein a liquid is in contact with the metal wire to form a first or second intermediate layer around the metal wire. 21. The intermediate layer forming apparatus according to claim 20, wherein a baking means is provided between said first storage tank and said second storage tank. 22. An external terminal and a lead of the semiconductor chip are connected by a covering wire in which a surface of a metal wire is covered with an insulator,
In the semiconductor device in which the covering wire and the connecting portion of the covering wire are covered with a resin, the covering wire is extended so as not to contact the corner of the semiconductor chip, the corner of the tab, or the corner of the lead. Semiconductor device.