JP2733282B2 - Semiconductor device and wire bonding method thereof, and wire bonding device and manufacturing method of the semiconductor device - Google Patents

Abstract

PURPOSE:To efficiently prevent short-circuit between wires, etc., and to improve bonding efficiency by forming a wire, which is straddling a lead arranged above a semiconductor chip in a resin-sealed semiconductor device, of a covered wire. CONSTITUTION:In a lead-on chip type semiconductor device 1, a pair of inner leads 4A and 4B, which extend along the center in the longitudinal direction of a semiconductor chip 2, are inner leads for Vcc and Vss, and the inner leads 4A and 4B, the inner leads 4 (external electrodes), being arranged on both sides of this inner lead 4, and the bonding pads 4 are connected respectively by wires. Among these wires, wires which are straddling the inner lead 4A for Vcc and the inner lead 4B for Vss are made of covered wires 6 that the metallic wires such as Au, Cu, Al, etc., are covered with insulating films. And by these wires 6, short circuits between the inner lead 4A for Vcc or the inner lead 4b for Vss and the wires straddling them are prevented surely.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, a wire bonding technology thereof, and a semiconductor device manufacturing technology, and more particularly, to a semiconductor device in which a semiconductor chip and inner leads are covered with an insulating film. The present invention relates to a technology effective when applied to each technology of a semiconductor device to be connected.

[Conventional technology]

For example, as a semiconductor device, in order to prevent a short circuit of a wire between a semiconductor chip and an inner lead, there is a device in which the wire is formed by a covered wire covered with an insulating covering film (see, for example, Japanese Unexamined Patent Application, First Publication No. H11-163873). Showa 53-96669
No., JP-A-61-3420, JP-A-58-155852, JP-A-60
-66029).

In addition, the present applicant has proposed a semiconductor device in which wires crossing each other are formed by a covering wire and a manufacturing technique thereof (Japanese Patent Application Nos. 63-69436 and 6
3-190163, Japanese Patent Application No. 63-265526).

[Problems to be solved by the invention]

However, in the semiconductor device technology described above,
The present inventors have clarified that the following problems to be solved remain.

That is, in the covering wire bonding technique, unlike the ordinary bare wire bonding technique, a step of breaking / removing a part of the covering film of the covering wire derived from the bonding tool by heating or the like is required, or The unwinding speed of the coated wire is low due to poor slippage of the coated wire. Therefore, if all the wires are formed of the coated wire, the bonding efficiency is reduced.

Therefore, it has been clarified by the present inventor that in order to improve the bonding efficiency, the coated wire should be used only for the wire that is likely to cause a short circuit.

By the way, for example, the risk of such a short-circuit is more likely to occur in a long-distance wire than in a short-distance wire because of the magnitude of the deformation amount. It is conceivable that the wire is formed at a longer distance than the other wires because it is located above the other wires.

That is, for example, there is a case where one wire is formed over a long distance by bonding one wire over another wire.

In this case, if the long-distance wire is used as the covering wire and the short-distance bare wire bonding step is performed after the long-distance covering wire bonding step, the long-distance covered wire can be bonded to the short-distance bare wire. It becomes an obstacle at the time and wire bonding becomes difficult.

Therefore, it has been clarified by the present inventors that it is necessary to consider the above points in a wire bonding technique of a semiconductor device in which a covered wire is used as a part of the wire.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor device capable of efficiently preventing a short circuit between wires and the like in a bonding technique using a covered wire and improving the bonding efficiency, a wire bonding technique for the semiconductor device, and a semiconductor device. It is to provide a manufacturing technology.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of this specification and the accompanying drawings.

[Means for solving the problem]

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

First, among a plurality of wires connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode, a part of the wires is formed by a covered wire covered with an insulating covering film. The semiconductor device is a resin-encapsulated semiconductor device having a structure in which the wire extending over a lead disposed above the semiconductor chip is formed by the covering wire.

Second, electrodes formed on the semiconductor chip are alternately arranged in two rows in a staggered manner along at least one side edge of the semiconductor chip, and electrodes in an inner row and an outer row of the semiconductor chip, An external electrode disposed outside the semiconductor chip along one side edge thereof corresponding to each of the electrodes, wherein the external electrodes are connected by wires, and the electrodes in the inner row, the external electrodes, Is formed by a coated wire coated with an insulating coating film, and a wire connecting the outer row of electrodes and the external electrodes is not coated with an insulating coating film. This is a semiconductor device having a structure formed by:

Third, the electrodes formed on the semiconductor chip are arranged at least along one side edge of the semiconductor chip, and correspond to the electrodes of the semiconductor chip, and are arranged on the outside along the one side edge of the semiconductor chip. A semiconductor device in which the tips of the arranged external electrodes are alternately arranged outside the semiconductor chip along one side edge in a staggered manner, and the electrodes of the semiconductor chip and the tips of the external electrodes are connected by wires. Wherein the long-distance wire is formed by a coated wire coated with an insulating coating film, and the short-distance wire is formed by a bare wire not coated with an insulating coating film. The semiconductor device has a structure as described above.

Fourth, a resin-encapsulated semiconductor device including a first semiconductor chip and a second semiconductor chip sealed in a single resin-encapsulated body, wherein the first semiconductor chip has an electrode and a second semiconductor chip. A plurality of electrodes of a semiconductor chip are arranged to face each other, one of the wires adjacent to each other is formed by a covered wire covered with an insulating coating film, and the other is a bare wire not covered with an insulating coating film. This is a semiconductor device having a structure formed by wires.

Fifth, of the plurality of wires connecting the electrodes formed on the semiconductor chip mounted on the tab and the external electrodes corresponding to the electrodes, some of the wires were covered with an insulating coating film. A resin-sealed semiconductor device formed by a covering wire, wherein the wire straddling a tab suspension lead is formed by the covering wire.

Sixth, among a plurality of wires connecting the electrodes of the semiconductor chip and the external electrodes corresponding to the electrodes, a resin seal formed by a covered wire in which some of the wires are covered with an insulating covering film. A stationary type semiconductor device, wherein a wire connecting an electrode disposed on one side of the semiconductor chip and an external electrode disposed on another side adjacent to one side of the semiconductor chip is covered with the coating. This is a semiconductor device having a structure formed by wires.

Seventh, the wire connecting the electrode formed on the semiconductor chip and the electrode corresponding to this electrode is covered with an insulative coating film and uncoated with an insulative coating film. A wire bonding method or a wire bonding apparatus for a semiconductor device formed by using a wire, wherein the bonding step of the covering wire is performed after the bonding step of the bare wire.

Eighth, a wire connecting the electrode formed on the semiconductor chip and an external electrode corresponding to this electrode is covered with an insulating coating film and bare and not covered with an insulating coating film. A method of manufacturing a semiconductor device formed by a wire, after the bonding step of the bare wire,
A method of manufacturing a semiconductor device, comprising performing a bonding step of the covered wire, and then sealing the semiconductor chip, the electrode, the external electrode, and the wire with a resin to manufacture a semiconductor device.

[Action]

According to the first means, among the plurality of wires,
A part of the wire is formed by a covered wire covered with an insulating covering film, and the covered wire straddles a lead disposed above the semiconductor chip, i.e., straddles the lead. Therefore, since the wire which is located above the other wires and whose deformation amount is increased over a long distance is usually used as the covering wire, it is possible to surely prevent the short-circuit at a place where the short-circuit is likely to occur.

According to the second means, electrodes arranged alternately in two rows in a zigzag pattern on the semiconductor chip along one side edge thereof and the external electrodes are connected by wires, respectively. Because the wires between the electrodes of the row and the external electrodes are connected to the electrodes of the inner row,
Since the wire whose deformation is increased over a long distance is a covered wire, it is possible to reliably prevent a short circuit between the wires in the staggered electrode arrangement, and to prevent the staggered electrode arrangement and the short circuit. Thus, the distance between the electrodes can be reduced.

According to the third means, the electrodes arranged on the semiconductor chip along one side edge thereof and the tips of the external electrodes alternately arranged in a staggered shape outside the semiconductor chip along one side edge thereof Are connected by a wire, and among the wires,
Among the wires, the long-distance wire is formed by the coated wire coated with the insulating coating film, so that a short circuit between the wires in the staggered external electrode array can be reliably prevented. In addition, the staggered arrangement of the external electrodes and the prevention of short-circuit can reduce the distance between the external electrodes.

According to the fourth means, the first electrode arranged along one side edge on the first semiconductor chip is opposed to the first electrode at a predetermined interval on the second semiconductor chip. The second electrode disposed along one side edge is connected, and one of the wires adjacent to each other is formed by the covering wire, and the other is formed by the bare wire. Compared to the distance between the electrodes of the semiconductor chip connected to the external electrodes, since the connection is usually made to the first electrode and the second electrode whose distance is narrowed,
It is possible to reliably prevent a short circuit between the wires or the like, which is likely to cause a short circuit.

According to the fifth means, of the plurality of wires connecting the electrodes on the semiconductor chip and the external electrodes corresponding to the electrodes, some of the wires are formed by the covering wires, and the covering wires are formed on the tab suspension leads. Since the wire that straddles the wire, that is, straddles the tab suspension lead, the wire whose deformation is larger over a longer distance than the other wires is usually used as the covering wire. Short circuits can be reliably prevented.

According to the above-described sixth means, of the plurality of wires connecting the electrodes on the semiconductor chip and the external electrodes corresponding to the electrodes, some of the wires are formed by covered wires, and the covered wires are An electrode arranged on one side of the upper side and a wire connecting the electrode arranged on the outside of the other side of the semiconductor chip, that is, because the wire extends between the one side and the outside of the other side of the semiconductor chip, usually, Since the wire whose deformation is increased over a longer distance than the other wires is the covered wire, it is possible to reliably prevent a short circuit at a location where the short circuit is likely to occur.

Further, according to the first to sixth means, since the wire in each means is formed by the covering wire and the bare wire, the coating film is broken / removed in the bare wire bonding step. Since a process is not required and the feeding speed is higher than that of the coated wire, it is possible to improve bonding workability and bonding efficiency.

According to the seventh and eighth means, the bonding step of the covering wire is performed after the bonding step of the bare wire, so that, for example, the lower wire is
When bonding the upper wire as a covered wire, the covered wire does not hinder the bonding process of the lower bare wire, so the lower wire is a bare wire and the upper wire is a covered wire. An efficient short circuit can be prevented.

According to the ninth means, after the bonding step of the bare wire, the bonding step of the covering wire is performed, and then the resin sealing step is performed. When bonding as a covered wire, the covered wire does not become an obstacle during the bonding step of the bare wire below, so that the lower wire is used as a bare wire and the wire above is used as a A semiconductor device in which prevention is achieved can be manufactured.

Embodiment 1 FIG. 1 is a perspective view showing a semiconductor device according to an embodiment of the present invention with a part cut away, FIG. 2 is a plan view showing a lead frame used in the semiconductor device, and FIG. FIG. 4 is an explanatory view of a wire bonding apparatus according to an embodiment of the present invention, FIG. 4 is a schematic view showing a second bonding mechanism of the wire bonding apparatus, and FIG. 5 is an enlarged portion showing a surface state of an inner lead of the embodiment. FIG. 6 is a sectional explanatory view showing the structure of the semiconductor device, FIG. 7 is a sectional perspective view showing the structure of the covering wire, FIG. 8 is an explanatory view of a wear test, and FIG. 9 shows a wire supply system. FIG. 10 is a perspective view, FIG. 10 is an enlarged perspective view showing a main part of the airbag tensioner of the embodiment, FIG. 11 is a front view of the airbag tensioner, and FIG. 12 is an explanation showing an arrangement state of each mechanism near the bonding tool. Figure 13 shows the bonding tool It is an explanatory view showing a state of application of ultrasonic energy to Le.

As shown in FIG. 1, the semiconductor device of the present embodiment is a so-called Lead-on-Chip (Lead-on-Chip) type semiconductor device 1. On the upper surface of the semiconductor chip 2, a pair of polyimide films or the like is provided. The insulator 3 is bonded with a thermosetting epoxy-based bonding material or the like.

Also, on the pair of insulators 3, the inner leads 4, 4A, 4
B is arranged by being joined by a thermosetting epoxy-based joining agent or the like.

Bonding pads 5 (electrodes) are arranged between the pair of insulators 3 and on the upper surface of the semiconductor chip 2 at both ends in the longitudinal direction of the insulators 3.

A pair of inner leads 4A and 4B extending along the center in the longitudinal direction of the semiconductor chip 2 are Vcc and Vss inner leads, and are provided on the inner leads 4A and 4B and on both sides of the inner leads 4A and 4B. The disposed inner leads 4 (external electrodes) and the bonding pads 5 are respectively connected by wires.

Of the wires, inner leads 4A and V for Vcc
The wire extending over the inner lead 4B for ss is formed of a coated wire 6 in which an insulating film is coated on a metal wire made of, for example, gold (Au), copper (Cu), aluminum (Al), and the like. The covering wire 6 reliably prevents a short circuit between the inner lead 4A for Vcc or the inner lead 4B for Vss and a wire straddling the inner lead 4A for Vcc or the inner lead 4B for Vss due to a wire flow or the like.

The wires other than the covering wire 6 straddling the inner lead 4A for Vcc and the inner lead 4B for Vss are formed of bare wires 7 made of only the same metal wires as described above.

In this case, the covering wire 6 is connected to the inner leads 4A, 4B
Because it straddles above, it is located above the bare wire 7,
In addition, it is formed longer than the bare wire 7.

As described above, the wires of the semiconductor device 1 of the present embodiment are formed by the covering wires 6 and the bare wires 7.

This requires a step of breaking or removing a part of the coating film of the coating wire 6 derived from the bonding tool by heating or the like, as described later, when bonding the coating wire 6. This is to prevent the workability and bonding efficiency of the wire from being reduced if the entire wire is formed of the coated wire 6 because of the poor slip of the wire.

In this embodiment, a wire straddling the inner leads 4A and 4B is the covering wire 6.

This is because the wire straddling the inner leads 4A, 4B straddles the inner leads 4A, 4B,
This is because the wire is located above the other wire and is formed at a long distance, so that the wire is more easily deformed than the other wire, and therefore, there is a high possibility of a short circuit due to a wire flow or the like.

That is, in the semiconductor device 1 according to the present embodiment, by using the covering wire 6 only for the wire that is likely to be short-circuited, it is possible to prevent the above-described reduction in the workability and the bonding efficiency of the bonding and to reduce the accompanying wire. Prevention of short circuit is efficiently achieved, and reduction of wire cost is achieved.

Semiconductor chip 2, bonding pad 5, covering wire 6, bare wire 7, inner leads 4, 4 thus configured
A and 4B are resin-sealed by transfer molding to form a package body 8. Outer leads 9 on each extension of the inner leads 4, 4A and 4B are projected from the outer peripheral surface of the package body 8 and bent. Is molded.

In this embodiment, in particular, a short circuit due to a wire flow during the formation of such a package body 8, that is, a short circuit between the wires, the wires and the inner leads 4, 4A, 4
The short circuit between B and the short circuit between the wire and the semiconductor chip 2 is prevented by the covering wire 6.

The lead frame 10 used in the semiconductor device according to the present embodiment has a guide hole 10 for transportation or the like as shown in FIG.
A plurality of unit frames having A are connected in the horizontal direction in FIG.

Next, the wire bonding apparatus 11 of the present embodiment used for the wire bonding of the semiconductor device 1 will be described.

The wire in the semiconductor device of the present embodiment is formed by the covering wire 6 and the bare wire 7 as described above.

For this reason, the wire bonding apparatus 11 of the present embodiment
For example, as shown in FIG. 3, a first bonding mechanism 11A for bonding the bare wire 7 and a second bonding mechanism 11B for bonding the covering wire 6 are arranged along the transport line 12 of the lead frame 10 to be wire-bonded. Although they are arranged side by side, the two structures are basically the same, so the second bonding mechanism 11B will be described, and the first bonding mechanism 11A will be omitted.

The schematic configuration of the second bonding mechanism 11B in the wire bonding apparatus 11 is as shown in FIG.
XY with bonding head 13 as drive mechanism
It has a stage 14, a bonding stage 15 on which the lead frame 10 is mounted, and a control unit 16 for controlling the operation of these.

The control unit 16 performs overall control of the wire bonding apparatus 11, and is configured by, for example, a microcomputer system including a microprocessor and a memory, and is a system capable of performing a bonding operation according to operating conditions set by an operator. .

The bonding stage 15 is formed so as to be movable up and down, and the lead frame 10 mounted on the bonding stage 15 is heated to a predetermined temperature by a heating source (not shown).

As shown in FIGS. 3 and 4, the lead frame 10 to which the bare wire 7 is bonded by the first bonding mechanism 11A is supplied onto the bonding stage 15 by a transport mechanism (not shown). .

The lead frame 10 supplied to the bonding stage 15 is in a state where the unit frames shown in FIG. 2 are connected five to six in the horizontal direction in FIG. 2, and the semiconductor chip 2 is already connected by a pellet bonding device (not shown). It is the one that is attached.

Such a lead frame 10 is, for example, Kovar,
It is obtained by processing a plate-like member having a thickness of about 0.15 mm such as 42 alloy or nickel alloy into a shape shown in FIG.

As shown in FIG. 5, a part of the tip surface of each of the inner leads 4, 4A, 4B (external electrodes) is formed of an uneven surface r. Such an uneven surface r is formed by first processing the lead frame 10 into the shape shown in FIG.
It can be formed by pressing the tip surfaces of A and 4B with an uneven punch. Also, in the same figure, a case is shown in which a cut is formed in a pattern at a part of the tip surface of the inner leads 4, 4A, 4B, but by further increasing the density of such irregularities, the inner leads 4, 4A, 4B are formed. 4A, 4B
May be roughened. Due to the function of the uneven surface r, the coated wire 6 described later is coated with the coating film 6A.
Destruction / removal is surely performed, the details of which will be described later.

Next, the semiconductor chip 2 mounted on the lead frame 10 will be described.

As shown in FIG. 6, an insulator 3 made of a polyimide film or the like is attached to the upper surface of the semiconductor chip 2 with a thermosetting epoxy-based bonding material 17A or the like. , Inner lead 4,4
A and 4B are joined and fixed by a thermosetting epoxy-based joining material 17B or the like.

Such a semiconductor chip 2 is obtained by slicing an ingot made of silicon (Si) obtained by a technique such as a single crystal pulling method in a crystal direction into a wafer state, and using a photoresist technique on the surface of the wafer. It is obtained by forming a microprocessor or a logic circuit or the like through an oxidation / diffusion process and then dividing (dicing) into a square shape.

The schematic configuration of each layer inside the semiconductor chip 2 will be briefly described. An upper layer of a chip substrate 18 made of silicon (Si) having a thickness of about 40 μm
A silicon oxide film 19 of about 0.45 μm is formed, and a PSG film 20 as an interlayer insulating film is formed thereon with a thickness of about 0.3 μm. A passivation film 21 as a protective film is deposited on the uppermost layer with a thickness of about 1.2 μm, a part of which is opened and has a thickness of aluminum (Al) partially provided in the lower layer. 0.8μm
The bonding pad 5 has a state in which the upper surface thereof is exposed to the upper outside.

As shown in FIG. 4, inside the bonding head 13 on the XY stage 14, a vertical movement block 24 is provided.
The vertical movement block 24 is provided so as to be able to move up and down by a guide shaft 25 provided in the vertical direction. A conversion ball screw mechanism 27 is provided. Therefore, the vertical movement block 24 can be moved up and down by a predetermined amount in accordance with the rotation of the servomotor 26.

The vertical movement block 24 has a bonding arm 30 rotatable in a vertical plane about a rotation shaft 28, and one end of the bonding arm 30 has an elasticity such as a spring fixed to the vertical movement block 24. It is urged upward by a means 32 in FIG. 4, so that a counterclockwise urging force acts on the bonding arm 30 with the operation of the up-down movement block 24. This elastic means 32
When the bonding tool 33 comes into contact with the bonding pads 5 of the semiconductor chip 2, these bonding pads 5 are prevented from being pressed more than necessary, and are prevented from being damaged or broken. I have.

An ultrasonic oscillator 34 is provided at the inner end of the bonding arm 30 on the side of the vertical movement block 24, and the bonding arm 30
A predetermined ultrasonic energy can be supplied to 30. In the present embodiment, the ultrasonic oscillator 34 is a control unit.
The control unit 16 has a structure in which the output energy is variably controlled based on the control signal of the control unit 16.The control unit 16 controls the ultrasonic oscillator 34 based on a program stored in a storage unit (not shown).
Is instructed to output the ultrasonic energy.

A bonding tool 33 (capillary) is provided at the tip of the bonding arm 30 to which the ultrasonic energy is transmitted.
Is provided. The covering wire 6 supplied from the wire spool 35 is inserted into the bonding tool 33 with its tip slightly projecting.

Next, the configuration of the covered wire 6 used in this embodiment will be described in detail.

As shown in FIG. 7, the covering wire 6 has a cross-sectional structure in which a covering film 6A is applied around a metal wire 6B.

The metal wire 6B of the covering wire 6 is made of gold (Au), copper (Cu) or aluminum (Al), like the bare wire 7.

As the coating film 6A, 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. The use of a heat-resistant polyurethane resin having such a composition as the coating film 6A is extremely useful for improving the thermal degradation and bonding properties of the coating film 6A, and further improving the peeling strength of bonding.

As specific characteristics of the coating film 6A, the number of times the coating film 6A was destroyed after 100 hours in an environment of 150 ° C. to 175 ° C. through 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 deterioration rate in reduction is within 20% as the constituent material of the coating film 6A.

Furthermore, when an actual wire bonding operation is performed with the covered wire 6, it is necessary that the bonding property does not cause a problem. According to the research results of the present inventors in this regard, the coating film at the time of forming the metal ball 6C described below.
It is desirable to use a material that is non-carbonizable when 6A is removed by heating.

The reason is as follows. That is, in the heating removal of the coating film 6A during the formation of the metal ball 6C described below, the coating film 6A melts above the metal ball 6C, but at this time, the coating film 6A is carbonized. In this case, the coating film 6A is carbonized without being decomposed at a heating temperature, for example, at a high temperature condition of about 1060 ° C. As a result, the carbonized coating film 6A adheres to and remains on the surface of the metal wire 6B so as to wrap the metal wire 6B immediately above the metal ball 6C. In the worst case, it may cause wire curl and even break.

Considering such facts comprehensively, it is necessary for the coating film 6A of the coating wire 6 to satisfy at least the following two conditions.

First, a temperature cycle test or a wear test under the experimental conditions shown in FIG.
Deterioration rate in reducing the number of times of destruction of the coating film 6A after 100 hours at a temperature of 75 ° C. must be 20% or less

Secondly, it should be made of a material that is non-carbonizable when the coating film 6A is removed by heating when forming the metal balls 6C.

The heat-resistant polyurethane as a constituent material of the coating film 6A satisfying the above conditions will be described more specifically.The heat-resistant polyurethane is a polymer component mainly containing a terephthalic acid-based polyol containing active hydrogen, and isocyanate. Is obtained by using It should be noted that “being a main component” here means that the case where the whole consists only of the main component is included.

Terephthalic acid-based polyol containing active hydrogen, using terephthalic acid and polyhydric alcohol, 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. Among the above, it is particularly 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, a compound having an active hydrogen, such as tolylene diisocyanate or xylylene diisocyanate, isocyanate group of a polyvalent isocyanate having at least two isocyanate groups in one molecule, such as phenol , Caprolactam and those blocked with methyl ethyl ketone oxime.
Such isocyanates are stabilized. Further, there may be mentioned those obtained by reacting the 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.

The present invention is to prepare a coating composition using the above-described raw materials, apply the coating composition to the metal wire 6B of the wire body, and form a coating film having a thickness of several μm, thereby forming the metal wire 6B of the wire body.
To obtain a coated wire 6 insulated from the periphery.

The coating composition includes a hydroxyl group 1 of a polyol component.
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 if it is less than 0.4 equivalent, the crazing characteristics of the resulting insulated wire will decrease, while the wear resistance of the coating film exceeding 4.0 equivalents will deteriorate. 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 accelerating 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.

It can be obtained by applying the coating composition as described above on the surface of the metal wire 6B of the wire body and baking it with a conventional baking coating apparatus.

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 at 200 to 300 ° C. for about 4 to 100 seconds. In short, the coating is baked at a temperature and for a time sufficient to substantially complete the curing reaction of the coating composition, and the coated wire 6 of this embodiment is obtained.

Regarding the thickness of the coating film 6A, a bonding tool
Although there is a slight change due to the ultrasonic energy and the thermocompression force of 33, for example, a film thickness of about 0.2 to 3 [μm] is desirable. That is, if the film thickness is small, the insulation reliability of the coating film 6A is lacking, and if the film thickness is large, it is difficult to remove the coating film 6A during bonding.

According to the study results of the present inventors, as a constituent material of the coating film 6A, in addition to the heat-resistant polyurethane having the above-described composition,
Commercially available polyurethane and formal also satisfy the requirement of non-carbonization, but the deterioration rate under the above conditions in reducing the number of breakage of the coating film 6A after 100 hours at 150 ° C. to 175 ° C. exceeds 20%. It is not suitable as the film 6A.

On the other hand, polyimide, polyamide, nylon, polyester, polyamide imide, polyester imide, etc. show carbonization when forming the metal balls 6C or when removing the coating film 6A by heating, so that it is used as the coating film 6A of the coating wire 6. Turned out to be inappropriate.

As shown in FIG. 9, in the wire bonding apparatus 11 of the present embodiment, the covered wire 6 having the above-described configuration is connected to the wire spool 3 around which the covered wire 6 is wound.
5, is supplied to the bonding tool 33 via the airbag tensioner 36, the sprocket 37 and the clamper 38.

The wire spool 35 is formed by, for example, performing an alumite treatment on a surface of a cylindrical aluminum metal. This alumite treatment is performed to improve mechanical strength and prevent generation of scratches. However, in order to prevent the covering wire 6 wound therearound from being charged, chrome (Cr) plating or the like may be applied to perform a surface treatment to provide conductivity. Further, the wire spool 35 itself may be made of a stainless alloy.

The wire spool 35 is supported by a spool holder 35A, and a rotation shaft 35B of the spool holder 35A is fixed to a main body of the wire bonding apparatus 11. The spool holder 35A is made of, for example, a grounded stainless alloy so that at least a part thereof has conductivity. Therefore, in the covering wire 6 wound around the spool holder 35A, the covering film 6
The static electricity charged to A is discharged through the stainless alloy part. Although not shown in detail, at one end of the winding start portion of the wound coated wire 6, the coating film 6A is removed and the metal wire 6B is exposed,
The exposed portion of the metal wire 6B is joined to the wire spool 35. Therefore, as shown in FIG. 9, the metal wire 6B of the covered wire 6 in the wound state is
35, the spool holder 35A, the rotating shaft 35B and the main body of the wire bonding apparatus 11 are connected to the reference potential GND. This reference potential GND has the same value as the reference potential GND of the arc generator 40 in this embodiment. In this manner, the metal wire 6B of the covered wire 6 is connected to the reference potential GND, so that the potential difference between the electric torch 41 and the metal wire 6B of the covered wire 6 is set to a specified value when forming a metal ball 6C described later. Since secure and stable generation of the arc Ac can be realized, the metal balls 6C can be reliably formed.

As shown in FIGS. 10 and 11, the airbag tensioner 36 has a pair of guide plates 36A through which the covering wire 6 can pass. The guide plate 36A is obtained by subjecting the surface of an aluminum alloy to an alumite treatment and further applying a chromium (Cr) plating to the surface thereof, but may be made of a stainless alloy or the like. Any structure can be used as long as the coating wire 6 can be prevented from being charged at least at the time of contact with the coating wire 6. As shown in FIG. 11, a plurality of projections 36B are provided on the surface of the guide plate 36A on the wire passage space α side. The projection 36B is formed between the covering wire 6 passing through the wire passage space α and the guide plate 36A.
The protrusion 36B acts to minimize the contact portion with the wire passage space α.
Is substantially in point contact with the guide plate 36A, thereby preventing the coating film 6A from being charged by contact friction. Therefore, the surface of the projection 36B also needs to have conductivity, and the surface thereof is made of chromium (C
The plating process such as r) or the protrusion 36B itself is made of a stainless alloy or the like. As a technique for obtaining such a structure of the projection 36B, the inner peripheral surface of the guide plate 36A may be projected using a processing technique such as pressing, or the inner peripheral surface of the guide plate 36A formed flat. The rod-shaped member constituting the protrusion 36B may be fixed by means of bonding or bonding.

A fluid supply pipe 4 is provided at one longitudinal end of the two guide plates 36A.
A metal adapter 43 connected to 2 is attached,
A fluid outlet 44 is provided at an end face of the adapter 43. A flat spacer 45 projects from the periphery of the fluid outlet 44 in the longitudinal direction. The thickness of the spacer 45 determines the width of the wire passage space α. The width of the wire passage space α determined in this way differs depending on the diameter of the covering wire 6 to be used or the height of the protrusion 36B, but is set to about 1 mm as an example.

The fluid supply pipe 42 connected to the adapter 43 is connected to a fluid supply source (not shown). This fluid source includes:
For example, a corona discharge means is built-in, and the ion gas separated by the ion is used as an electric current remover Gs in the adapter 43.
Is supplied from the fluid outlet 44 to the wire passage space α.

Therefore, according to the present embodiment, the airbag tensioner
It is possible to apply the back tension to the coated wire 6 which is the original purpose of 36, and it is also possible to remove static electricity from the coated wire 6 by using the current eliminator Gs. Further, as described above, the action of the projection 36B on the inner peripheral surface of the guide plate 36A causes the covering wire 6 and the guide plate 36A.
Since the contact with the (airbag tensioner 36) is substantially in a point contact state, the charging of the coating wire 6 due to the passage of the airbag tensioner 36 is also prevented.

The coated wire 6 supplied from the wire spool 35 and passing through the airbag tensioner 36 is inserted into the bonding tool 33 via the sprocket 37 and the clamper 38. The sprocket 37 is for accurately positioning the covering wire 6 with respect to the bonding tool 33, and is fixed to the main body of the wire bonding apparatus 11. The clamper 38 is for holding / opening the covering wire 6 inserted into the bonding tool 33, and has a structure in which the covering wire 6 is held from the side by opening and closing movement of the pair of clamper chips 38A.

In the present embodiment, the sprocket 37 and the clamper 38 which are in contact with the coated wire 6 are made of a conductive metal, thereby charging the coating film 6A of the coated wire 6 and removing static electricity from the coating film 6A. Is being planned. In addition,
When a conductive metal cannot be used due to abrasion resistance or the like as in the case of the clamper 38, an air outlet (not shown) for the current eliminator Gs similar to that described in the airbag tensioner 36 is provided. By performing the static elimination blow of the covering wire 6 and the member, it is also possible to realize the prevention of static electricity and the static elimination of the covering wire 6.

The bonding tool 33 located below the clamper 38 is covered with a cover 47 when forming the metal ball 6C as shown in FIG. The cover 47 is rotatable in the direction of arrow A in the figure, and is configured to insert the bonding tool 33 from the tool insertion opening 48 by this rotation and cover the bonding tool 33. The reason for providing such a cover 47 is, first, that
The semiconductor chip 2 or the inner leads 4 and 4 are scattered by the scattering of the coating film 6A that melts when the metal balls 6C are formed.
A, 4B, etc. are used to prevent contamination. Second, when the metal wire 6B of the coated wire 6 is made of an oxidizing material such as Cu, Al, etc., an antioxidant gas atmosphere (shield gas atmosphere) is used. This is to make it easier to hold Such a cover 47 can be made of, for example, a heat-resistant stainless steel alloy. Further, the cover 47 is provided with a cover 20 so that an operator can confirm the state of formation of the metal balls 6C therein.
It may be formed of a heat-resistant glass material having a property.

An electric torch 41 (arc electrode) is arranged at the bottom of the cover 47 as shown in FIG. The electric torch 41 is arranged at a position close to the tip of the metal wire 6B of the coated wire 6 led out from the tip of the bonding tool 33 (see FIG. 12), and generates an arc Ac between the two to form the metal ball 6C. It is configured to form. Such an electric torch 41 can be formed of tungsten (W) or the like that can withstand high temperatures.

The electric torch 41 has a hollow interior,
As shown in FIG. 12, it is configured to communicate with a suction pipe 51 connected to a suction device 50 to suck and remove a coating film piece or the like scattered by a cooling fluid CGs ejected from a fluid spray nozzle 52 described later. ing. The electric torch 41 and suction tube
The coating film piece sucked through 51 is sucked by an external suction device 50 and then discharged to the outside.

The electric torch 41 is electrically connected to the arc generator 40 via the suction tube 51. The suction pipe 51 is made of a conductive metal such as a stainless alloy, for example.
The electric torch 41 is fixed via an adhesive metal layer (not shown) such as an Ag-Cu brazing material. The suction tube 51 further fixes the cover 47 with a sandwiching member 53 interposed therebetween.
Therefore, the electric torch 41 and the cover 47
It is configured to be able to move together through 51.

As means for moving the suction tube 51, a support member 54 for fixedly supporting the suction tube 51, and the support member 54 is connected to an arrow A in FIG.
The crankshaft 55 includes a crankshaft 55 that rotates in the direction, and a drive source 56 such as an electromagnetic solenoid that rotates the crankshaft 55. The rotation of the crankshaft 55 is realized by the movement of a shaft 57 connected to the crankshaft 55 and movable in the direction of arrow B in FIG. The crankshaft 55
Although not shown, is rotatably supported by the main body of the wire bonding apparatus 11.

A fluid spray nozzle 52 is attached to the cover 47 having the rotary structure from the outside to the inside of the cover 47. FIG. 12 shows a supply mechanism of the cooling fluid CGs of the fluid spray nozzle 52. The covering wire 6 protruding from the bonding tool 33 in the cover 47 is supplied with the cooling fluid CGs to the protruding root. It is arranged to be able to supply.

Cooling fluid CGs ejected from the fluid spray nozzle 52
As shown in the figure, the coating film 6A melted by the arc Ac between the metal ball 6C and the electric torch 41 at the tip of the coating wire 6 is scattered and removed from the peripheral surface of the coating wire 6 as shown in FIG. The melted coating film 6A has a function of being cooled and hardened in a fixed amount to suppress the occurrence of resin pool, thereby preventing clogging in the bonding tool 33. From such a viewpoint, the fluid spray nozzle 52 is disposed at a position facing the covering wire 6 from an obliquely upper side in the figure in order to suppress melting of the covering film 6A, and the rear end side of the covering wire 6 ( From top) to tip (bottom)
The cooling fluid CGs is blown against the air.

It is desirable that such a fluid spray nozzle 52 be fixed to the cover 47 and not to the bonding tool 33 as in this embodiment. That is, when such a fluid spray nozzle 52 is fixed to the bonding tool 33, the weight of the bonding tool 33 increases, so that the load of ultrasonic vibration increases and bondability decreases. .

As the cooling fluid CGs, N ₂ , H ₂ , He, Ar, and clean air can be used. As shown in FIG. 12, a cooling device 60 (fluid source) is provided by a fluid spraying device 58 (fluid source). The fluid is supplied to the fluid spray nozzle 52 through a flow meter 61 and a fluid transfer pipe 62. At this time, a corona discharge means (not shown) may be provided in the fluid spraying device 58, and the ion gas (current-removing member Gs) subjected to ion separation may be used as the cooling fluid CGs. In this case, static electricity can be removed from the coated wire 6 immediately before the wire bonding operation, so that electrostatic breakdown of the semiconductor chip 2 due to charging of the coating film 6A can be prevented. According to the study by the present inventors,
In addition to the ion gas, it has been confirmed that the spraying of a gas with a mere N ₂ gas also has the effect of eliminating the charge of the coating film 6A.

The cooling device 60 is configured to actively cool the cooling fluid CGs below normal temperature. The cooling device 60 can be configured by, for example, an electronic cooling device utilizing the Peltier effect. Although the illustration is simplified in FIG. 12, the periphery of the fluid transfer pipe 62 between the cooling device 60 and the fluid spray nozzle 52 is configured to be covered with a heat insulating material 63, Cooling fluid in transfer pipe 62
The temperature rise of CGs is suppressed. Further, the fluid transfer pipe 62 itself may have a double pipe structure of an outer pipe and an inner pipe, and may be configured to actively cool even during the fluid transfer.

In FIG. 9, an arc generating device 40 shown in a range surrounded by a two-dot chain line includes a capacitor C1, a storage capacitor C2, an arc generating thyristor D activated by a trigger, and a resistor R. The DC power supply DC supplied to the arc generator 40 has, for example, a negative polarity of about -1000 to -3000 [V].

The DC power supply DC is connected to an electric torch 41 via a thyristor D and a resistor R, and the reference potential GND side is set to, for example, 0 [V]. In the figure, V and A indicate a voltmeter and an ammeter, respectively.

Next, a wire bonding method according to the present embodiment will be described.

First, according to the wire bonding method according to the present embodiment, the first bonding mechanism of the wire bonding apparatus 11 is used.
After the completion of the bonding of the bare wire 7 by 11A, the bonding of the covered wire 6 by the second bonding mechanism 11B of the wire bonding apparatus 11 is performed.

In this case, as described above, the wire bonding apparatus
Since the first bonding mechanism 11A of 11 has substantially the same configuration as the second bonding mechanism 11B, the method of bonding the bare wire 7 by the first bonding mechanism 11A is described in FIG. 4 showing the second bonding mechanism 11B. Hereinafter, the outline will be described with reference to the reference numerals.

The lead frame 10 supplied to the left end side of the transfer line 12 shown in FIG. 3 is placed on the bonding stage 15 of the first bonding mechanism 11A by a transfer mechanism (not shown).

The semiconductor chip 2 is already mounted on the lower side of the lead frame 10 via the insulator 3 as shown in FIG.

Next, the XY stage 14 is operated while the lead frame 10 is mounted on the bonding stage 15.
By the operation of the XY stage 14, the bonding head 13 is moved by a predetermined amount, and the bonding tool 33 is positioned immediately above the semiconductor chip 2.

In this state, the drive source 56 shown in FIG.
Moves in the direction of arrow A in the same figure, and the tip of the bonding tool 33 is covered by the cover 47.

Next, as shown in FIG.
A high voltage of about 00 to -3000 [V] is applied, and an arc Ac is applied between the electric torch 41 connected thereto and the tip of the bare wire 7 made of a metal wire protruding from the bonding tool 33.
Is generated. By the action of this arc Ac, the bare wire 7
Is melted to form a spherical metal ball.

After the metal ball is formed at the end of the bare wire 7 in this manner, the driving source 56 is operated again, the suction tube 51 is rotated, and the cover 47 is detached from the periphery of the bonding tool 33, and the bonding is performed. The tool 33 is opened.

In this state, when the servo motor 26 of the bonding head 13 is operated by a predetermined amount and the ball screw mechanism 27 is moved downward, the bonding tool 33 lands on a predetermined bonding pad 5 on the semiconductor chip 2.

When the ultrasonic oscillator 34 is operated under the control of the control unit 16 while maintaining the landing state, predetermined ultrasonic vibration is transmitted from the bonding arm 30 to the bonding tool 33.

At this time, the urging force due to the operation of the vertical movement block 24,
The metal ball of the bare wire 7 is joined to the bonding pad 5 by the synergistic effect of the ultrasonic vibration and the heating (first bonding).

Next, when the servo motor 26 is driven, the bonding tool 33 moves up above the semiconductor chip 2. Further XY
When the stage 14 is operated, the bonding tool 33
Moves while piercing the bare wire 7 from its tip and reaches just above a predetermined portion of the inner lead 4.

Next, when the servomotor 26 operates, the bonding tool 33 lands on a predetermined portion of the inner lead 4.

The distal end of the bare wire 7 is joined to the surface of the inner lead 4 by the synergistic effect of the predetermined long-wave vibration transmitted to the bonding tool 33 and the heating of the inner lead 4 of the XY stage 14. You.

The wire bonding step of the bare wire 7 ends as described above.

Next, the step of bonding the covered wire 6 by the second bonding mechanism 11B of the wire bonding apparatus 11 will be described.

First, the lead frame in which the wire bonding step of the bare wire 7 has been completed by the first bonding mechanism 11A
4 is mounted on the bonding stage 15 of the second bonding mechanism 11B by a transport mechanism (not shown) from above the bonding stage 15 of the first bonding mechanism 11A, as shown in FIG.

Next, with the lead frame 10 placed on the bonding stage 15 of the second bonding mechanism 11B,
The XY stage 14 is operated. By the operation of the XY stage 14, the bonding head 13 is moved by a predetermined amount, and the bonding tool 33 is positioned immediately above the semiconductor chip 2.

In this state, the drive source 56 shown in FIG.
Moves in the direction of arrow A in the same figure, and the tip of the bonding tool 33 is covered by the cover 47.

Next, as shown in FIG.
A high voltage of about 00 to -3000 [V] is applied, and an arc Ac is generated between the electric torch 41 connected thereto and the tip of the metal wire 6B of the covering wire 6 protruding from the bonding tool 33. . By the action of the arc Ac, the tip of the metal wire 6B is melted to form a spherical metal ball 6C. At this time, the coating film of the coating wire 6 is formed by the heat of the arc Ac.
6A melts from the direction of the wire tip, the coating film 6A in this portion is removed, and the surface of the metal wire 6B is exposed.

It is desirable that the formation of the metal ball 6C be performed in as short a time as possible. At this time, by forming the metal balls 6C with high energy (high current, high voltage), the amount of the coating film 6A of the coating wire 6 that has melted can be reduced. Performing the formation of the metal ball 6C in a short time and with high energy in this way means stabilizing the state of the arc Ac generation. In this embodiment,
As described above, with the electric torch 41 at a negative potential of about -1000 to -3000 [V], the metal wire 6B
Is fixed and held at the reference potential GND (= 0 [V]), the arc Ac is also stable, and the increase and dispersion of the melting amount are suppressed.

Further, when forming the metal ball 6C, the cover
Fluid spray nozzle for bonding space surrounded by 47
The cooling fluid CGs passes through the coating film 6A of the coating wire 6 through 52.
It is sprayed on the melted part. By spraying the cooling fluid CGs, the melted coating film 6A is scattered, and the suction device is passed through the electric torch 41 and the suction pipe 51.
It is sucked by 50 and removed outside the system.

The cooling fluid CGs from the fluid spray nozzle 52 is cooled to, for example, about −10 to 0 ° C. by the cooling device 60 shown in FIG. 12, and the cooling fluid CGs from the fluid spray nozzle 52 at this time is at a low temperature. To some extent, the amount of the covered wire 6 melted is reduced. That is, the cooling fluid CGs cooled by the cooling device 60 can actively cool the metal wire 6B, the coating film 6A, and the bonding tool 33 of the coating wire 6, and thus affect the other coating film 6A. The coating film 6A only in the portion where the arc Ac is generated can be melted without giving the effect, and the amount of the coating film 6A that has melted can be controlled.

After the metal ball 6C is formed as described above, the drive source 56 is operated again, the suction pipe 51 rotates, the cover 47 is detached from the periphery of the bonding tool 33, and the bonding tool 33 is opened. Becomes

In this state, when the servomotor 26 of the bonding head 13 is operated by a predetermined amount to move the ball screw mechanism 27 downward, the bonding tool 33 lands on a predetermined bonding pad 5 on the semiconductor chip 2.

When the ultrasonic oscillator 34 is operated under the control of the control unit 16 while maintaining the landing state (application of the first ultrasonic vibration), predetermined ultrasonic vibration is transmitted from the bonding arm 30 to the bonding tool 33. Conveyed.

At this time, the urging force due to the operation of the vertical movement block 24,
The metal ball 6C is joined to the bonding pad 5 by a synergistic effect of the ultrasonic vibration and the heating of the lead frame 10 (first bonding).

Next, the ultrasonic energy of the ultrasonic oscillator 34 is returned to the initial value under the control of the control unit 16 (see FIG. 13), and when the servomotor 26 is driven, the bonding tool 33 is moved above the semiconductor chip 2. To rise. When the XY stage 14 is further operated, the bonding tool 33 moves to the position 2 in FIG.
A path indicated by a dashed line is moved so as to jump over the inner lead 4B while protruding the covering wire 6 from the end thereof, and reaches just above a predetermined portion of the inner lead 4. Here, the “predetermined portion” indicates a portion where the above-mentioned uneven surface r is formed on the surface of the inner lead 4.

The ultrasonic energy generated by the ultrasonic oscillator 34 may be kept during the movement of the bonding tool 33.

By continuing the application of the ultrasonic energy, the suction of the coated wire 6 in the bonding tool 33 is prevented, and the wire feed from the tip of the bonding tool 33 is smooth. Deformation such as bending of the covered wire 6 due to the occurrence is prevented, and loop abnormalities are also suppressed.

When the servo motor 26 operates in this state, the bonding tool 33 lands on the uneven surface r of the inner lead 4. Next, the ultrasonic oscillator is controlled by the control unit 16.
When the 34 is actuated (the application of the second ultrasonic vibration), the abdomen of the covering wire 6 led out from the tip of the bonding tool 33 is slid in contact with the uneven surface r, and the covering film 6A in this portion is mechanically The metal wire 6B is exposed and is destroyed.

When the XY stage 14 is operated and the bonding tool 33 is moved outward (to the right in FIG. 6) on the inner lead 4 while the second ultrasonic vibration is continued, the control of the controller 16 is performed. As a result, the application state of the ultrasonic energy of the ultrasonic oscillator 34 is switched (third ultrasonic vibration), and the ultrasonic vibration is exposed by a synergistic effect of the ultrasonic vibration and the heating of the inner lead 4 on the XY energy 14. The portion of the metal wire 6B is joined to the surface of the inner lead 4.

The first (S1), second (S2) and third
FIGS. 13 (a) and 13 (b) show the transition of the ultrasonic energy due to the ultrasonic vibration of (S3). In the figure, the first and third ultrasonic vibrations (S1, S3) are formed by connecting a metal wire 6B to a bonding pad 5 or an inner lead 4.
Required for bonding with the second ultrasonic vibration (S2)
Is necessary for breaking the coating film 6A. According to the study of the present inventors, the ultrasonic energy required for the destruction and removal of the coating film 6A is not always at the level of the ultrasonic energy required for the bonding, and the ultrasonic frequency and the like at the time of the bonding are also not considered. Low frequency ones have been found to be more effective.

Therefore, in the present embodiment, as shown in the figure, by controlling the ultrasonic oscillator 34 so as to obtain the optimum ultrasonic energy output for the purpose of applying the ultrasonic vibration, the efficient removal of the coating film 6A is achieved. And metal wire 6B and bonding pad 5
And the inner lead 4 can be joined.
In the figure, the first and third ultrasonic vibrations (S
Although the levels of the ultrasonic energy in (1, S3) are set to be equal, the level of the ultrasonic energy may be changed to a different level according to the temperature condition due to heating or the like.

As described above, in this embodiment, by controlling the ultrasonic energy of the ultrasonic oscillator 34 variably by the control unit 16, it is possible to efficiently remove the coating film 6A and improve the bonding reliability. Has become.

Further, in the present embodiment, since the portion where the coating film 6A is removed and the portion where the bonding is performed are different portions on the inner lead 4, the bonding portion is kept clean, and the coating film 6A Bonding failure due to contamination such as is prevented.

Further, when the coating film 6A is removed, since the surface of the inner lead 4 is constituted by the uneven surface r, the remaining of the coating film 6A can be reliably prevented, and the metal wire 6B and the inner lead can be removed. 4 can be increased in bonding strength.

After the completion of the wire bonding process as described above, the lead frame 10 is placed in a mold (not shown), and a molten resin such as an epoxy resin is injected into the mold at a high pressure, as shown in FIG. The package body 8 of the resin-sealed semiconductor device 1 is formed. At this time, particularly in the second bonding, the bonding between the metal wire 6B and the inner lead 4 is performed in a state where the coating film 6A is incompletely peeled and the coating film 6A remains on the surface of the inner lead 4. In this case, there is a possibility that a wire flow or a breakage of the coated wire 6 may occur with the injection pressure of the molten resin. In this regard, in this embodiment, as described above, the coating film 6A is almost completely peeled off by the control of the application of the ultrasonic vibration and the destruction / removal of the coating film 6A by the sliding contact with the uneven surface r of the inner lead 4 surface. Therefore, the exposed metal wire 6B and the inner lead 4 are securely joined, and the wire flow and the breakage of the coating wire 6 are effectively prevented.

After the molten resin thus formed is cured,
The lead frame 10 on which the package body 8 is formed is taken out of the mold.

Next, a resin-sealed semiconductor device 1 shown in FIG. 1 is obtained by processing and molding the outer leads 9 protruding from the side surfaces of the package body 8.

Embodiment 2 FIG. 14 is a partial plan view showing a semiconductor device according to another embodiment of the present invention.

The semiconductor device 1 of the second embodiment is formed by the lead frame 10 shown in FIG.

The lead frame 10 includes a tab 10C supported substantially at the center thereof by a tab suspension lead 10B, and inner leads 4 (external electrodes) extending from the tab 10C in four plane directions in a non-contact state with the tab 10C. ).

The respective inner leads 4 are connected to each other by a frame (not shown) at the outer peripheral portion in FIG.

In the semiconductor device 1 according to the second embodiment, the package body 8 is formed by resin molding using such a lead frame 10, and the four sides of the package body 8 are bent outside in a crank shape (gull wing shape). An outer lead (not shown) to be processed is projected.

Tab 10C embedded in the center of the package body 8
On the upper side, the semiconductor chip 2 is mounted via a bonding agent such as a silver paste.

Bonding pad 5 formed on semiconductor chip 2
The inner lead 4 has a structure in which conduction is provided by a covering wire 6 and a bare wire 7 stretched in a loop shape.

The bonding pads 5 on the semiconductor chip 2 are alternately arranged in two rows along the four side edges of the semiconductor chip 2 in a staggered manner, while the inner leads 4 have tips at the four side edges of the semiconductor chip 2. It is arranged so that it may be located in two rows along the outside in a staggered manner.

The semiconductor device 1 of the second embodiment has such an arrangement,
They are located respectively alternately along the interval four-side edges of the semiconductor chip 2 to the short-range l ₁ and long-distance l ₂ between the bonding pads 5 corresponding thereto and wire connection point 4C of the tip of each inner lead 4 It is formed as follows.

The bare wire 7 is bridged and the bonding pad 5 corresponding thereto and wire connection point 4C of the tip of the inner lead 4 which correspond to each other at intervals of a short distance l _1, while the covering wire 6 has a length distance l ₂ of being bridged and the bonding pad 5 corresponding thereto and the tip of the wire connection point 4C of the inner lead 4 which correspond to each other at intervals.

For this reason, the covered wire 6 has a longer distance than the bare wire 7.

Therefore, the covered wire 6 is longer than the bare wire 7 and has a larger deformation amount.
Bare wire 7, Semiconductor chip 2, Tab suspension lead 10B, Tab 10C
However, since the covered wire 6 is covered with the insulating film 6A, a short circuit due to such contact is prevented.

Further, by preventing such a short circuit by the covering wire 6, the pitch between the bonding pads 5 arranged in a staggered manner and the pitch between the inner leads 4 can be further reduced, so that the semiconductor device can be formed. High integration of
Higher functionality can be improved.

Further, in the second embodiment, as in the first embodiment, since the wire is formed by the covering wire 6 and the bare wire 7, the above-described effect can be obtained without lowering the workability and efficiency of the bonding. Since the wire bonding can be performed by the same method and apparatus as in the first embodiment,
The same effects as those of the first embodiment can be obtained with respect to the wire bonding technique and the semiconductor device manufacturing method.

Third Embodiment FIG. 15 is a schematic plan view showing a semiconductor device according to another embodiment of the present invention.

The semiconductor device 1 according to the third embodiment is a semiconductor device for signal processing for a DAT (digital audio tape), and a single Bip chip 2A (first semiconductor chip 2) and a single CMOS chip 2B (second semiconductor chip 2) are used. It is sealed by being juxtaposed in a resin sealing body 8A made of a resin mold.

A plurality of Bip chips 2A bonding pads 5A (first electrodes) and a plurality of bonding pads 5B (second electrodes) of the CMOS chip 2B are electrically connected to each other by a covering wire 6 and a bare wire 7, The coated wires 6 and the bare wires 7 are alternately arranged in parallel with each other along the vertical direction in FIG.

That is, one of the wires connected to the bonding pads 5A and 5B adjacent to each other is formed by the covering wire 6, and the other is formed by the bare wire 7.

The semiconductor device of the second embodiment uses an Aud
Although the io signal is A / D converted, the digital output is PWM by three longitudinal integration, and the signal is processed by the CMOS chip 2B to be a complete digital signal.

In this case, if there is a parasitic capacitance or noise in the line from the Bip chip 2A to the CMOS chip 2B, jitter occurs and the accuracy decreases, but the Bip chip 2A and the CMOS chip 2B are bonded by the covering wire 6. Therefore, it is possible to reduce the adverse effect.

In the above case, the covered wire 6 and the bare wire 7 are bridge-bonded in parallel with each other between the Bip chip 2A and the CMOS chip 2B. In the third embodiment, for example, the covered wire 6 and the bare wire 7 may be cross-bonded so as to cross each other.

According to the third embodiment, in particular, the Bip chip 2A and the CMO
The distance between the bonding pads 5 of the S chip 2B is usually smaller than the pitch between the inner leads (not shown) and the bonding pad on the Bip chip 2A or the CMOS chip 2B connected to the inner leads. Since the width is reduced, a wire shot or the like is likely to occur, but the wire shot can be reliably prevented by forming one of the wires where there is a possibility that the wire is formed by the covering wire 6.

Embodiment 4 FIG. 16 is a plan view showing a semiconductor device according to another embodiment of the present invention.

The semiconductor device 1 of the fourth embodiment is a resin-encapsulated semiconductor device, and among a plurality of wires connecting the bonding pad 5 of the semiconductor chip 2 and the inner lead 4, a wire straddling the tab suspension lead 10B is used. It is formed by the covering wire 6.

According to the semiconductor device of the fourth embodiment, the tab suspension lead
A wire straddling 10B is formed by the coated wire 6,
Since the coated wire 6 straddles the tab suspension lead 10B, it has a longer deformation distance than the other bare wire 7 and therefore has a larger deformation amount. Can be reliably prevented.

Embodiment 5 FIG. 17 is a plan view showing a semiconductor device according to another embodiment of the present invention.

The semiconductor device 1 according to the fifth embodiment is a resin-encapsulated semiconductor device, in which a bonding pad 5 disposed on one side of the semiconductor chip 2 and a bonding pad 5 disposed outside the other side of the semiconductor chip 2 are disposed. A wire connecting the bonding pad 5 is formed by the covering wire 6.

According to the semiconductor device of the fifth embodiment, the semiconductor chip 2
Since the wire connecting the bonding pad 5 arranged on one side of the semiconductor chip 2 and the inner lead 4 arranged along the other side of the semiconductor chip 2 adjacent to the one side is a long distance, the semiconductor chip 2 etc. Short-circuiting due to contact with the wire is likely to occur, but such a short-circuit can be reliably prevented by forming the wire with the covering wire 6.

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 it is needless to say that various modifications can be made without departing from the gist of the invention. Nor.

For example, in the above embodiment, the inner lead 4
Are external electrodes, but the external electrodes in the present invention may be wiring formed on a substrate on which the semiconductor device 1 is mounted.

Further, in the wire bonding method and the wire bonding apparatus 11 of the above embodiment, the lead frame 10 is transported on the transport line 12, and the bare wire is placed on each bonding stage of the first bonding mechanism 11A and the second bonding mechanism 11B. The wire bonding between the bare wire 7 and the coated wire 6 is performed by the first bonding mechanism 11A and the second bonding mechanism 11B on a single bonding stage. That is, a predetermined wire bonding is performed by moving the first bonding mechanism 11A and the second bonding mechanism 11B with respect to the lead frame 10 without moving the lead frame 10 side. It is good also as composition.

In the wire bonding method and the wire bonding apparatus 11 of the above embodiment, the case where a capillary is used as the bonding tool 33 is illustrated,
The invention is not limited to this, and a knife-shaped wedge may be used.

〔The invention's effect〕

The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.

In other words, according to the semiconductor device of the first aspect, a part of the plurality of wires is formed by the covering wire covered with the insulating covering film, and the covering wire is formed on the upper side of the semiconductor chip. The wire that straddles the lead arranged in the above, that is, the wire that straddles the lead and is usually located above the other wires and has a large deformation over a long distance is a covered wire. Therefore, it is possible to reliably prevent a short circuit at a place where the short circuit is likely to occur.

According to the semiconductor device of the third aspect, electrodes arranged alternately in two rows on the semiconductor chip in a staggered manner along one side edge thereof and the external electrodes are connected by wires, respectively.
Of the wires, the wires between the electrodes in the inner row and the external electrodes, that is, wires that are connected to the electrodes in the inner row, so that the wire whose deformation amount is large over a long distance are usually covered wires. Therefore, a short circuit between the wires in the staggered electrode arrangement can be reliably prevented, and the staggered electrode arrangement and the prevention of the short circuit can narrow the electrodes.

According to the semiconductor device of the fourth aspect, the electrodes are arranged on the semiconductor chip along one side edge thereof and the external electrodes are alternately arranged along the one side edge of the semiconductor chip outside in a staggered manner. The tip of the electrode is connected by a wire, and among the wires, a long-distance wire is formed by a covering wire covered with an insulating covering film. In this case, the short circuit between the wires can be reliably prevented, and the staggered arrangement of the external electrodes and the prevention of the short circuit can reduce the distance between the external electrodes.

6. The semiconductor device according to claim 5, wherein the first electrode is arranged along one side edge on the first semiconductor chip, and the second semiconductor is opposed to the first electrode at a predetermined interval. A second electrode arranged along one side edge on the chip is connected, and one of the wires adjacent to each other is formed by a covering wire, and the other is formed by a bare wire. And the distance between the electrodes of the semiconductor chip connected to this external electrode,
Normally, a short circuit between the wires and the like, which is likely to be short-circuited because it is connected to the first electrode and the second electrode whose intervals are small, can be reliably prevented.

According to the semiconductor device of the sixth aspect, of the plurality of wires connecting the electrodes on the semiconductor chip and the external electrodes corresponding to the electrodes, some of the wires are formed by the covering wire, and the covering wire is formed by the tab. Because the wire straddling the suspension lead, that is, straddling the tab suspension lead, the wire whose deformation is larger at a longer distance than other wires is generally used as the covering wire, and there is a risk of short-circuiting. Short circuits at many locations can be reliably prevented.

According to the semiconductor device of the seventh aspect, of the plurality of wires connecting the electrodes on the semiconductor chip and the external electrodes corresponding to the electrodes, some of the wires are formed by the coated wires, and the coated wires are formed of the semiconductor. A wire connecting the electrode arranged on one side of the chip and the electrode arranged outside the other side of the semiconductor chip, that is, because the wire extends between the one side and the outside of the other side of the semiconductor chip, Since the wire whose deformation is increased over a longer distance than the other wires is the covered wire, it is possible to reliably prevent a short circuit at a location where the short circuit is likely to occur.

According to the above-described semiconductor device, since each of the wires is formed by the covering wire and the bare wire, the process of breaking / removing the covering film is unnecessary in the bonding process of the bare wire. Since the feeding speed is higher than that of the coated wire, bonding workability and bonding efficiency can be improved.

According to the wire bonding method and the wire bonding apparatus according to claims 8 and 9, after the bonding step of the bare wire, the bonding step of the covering wire is performed, for example, the lower wire is a bare wire, the upper wire When bonding as a covered wire, the covered wire does not become an obstacle during the bonding step of the bare wire below, so that the lower wire is a bare wire, and the upper wire is an efficient short circuit. Can be prevented.

According to the manufacturing method of claim 10, after the bonding step of the bare wire, the bonding step of the coated wire is performed, and then, the resin sealing step is performed,
For example, when bonding the lower wire as a bare wire and the wire above it as a covering wire, the covering wire does not become an obstacle during the bonding process of the lower bare wire, so the lower wire is used as a bare wire,
It is possible to manufacture a semiconductor device in which a short circuit is efficiently prevented by using the wire above it as a covering wire.

[Brief description of the drawings]

1 is a partially cutaway perspective view showing a semiconductor device according to an embodiment of the present invention, FIG. 2 is a plan view showing a lead frame used in the semiconductor device, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a schematic view showing a second wire bonding mechanism of the wire bonding apparatus, FIG. 5 is an enlarged partial perspective view showing a surface state of an inner lead of the present embodiment, 6 is a cross-sectional explanatory view showing the structure of the semiconductor device, FIG. 7 is a cross-sectional perspective view showing the structure of the covered wire, FIG. 8 is an explanatory view of the wear test, FIG. 9 is a perspective view showing a wire supply system, FIG. 10 is an enlarged perspective view showing an essential part of the airbag tensioner of the embodiment, FIG. 11 is a front view of the airbag tensioner, FIG. 12 is an explanatory diagram showing an arrangement state of each mechanism near the bonding tool, Figure 13 shows bondin FIG. 14 is an explanatory view showing a state of application of ultrasonic energy to a tool. FIG. 14 is a partial plan view showing a semiconductor device according to another embodiment of the present invention. FIG. 15 is a semiconductor device according to another embodiment of the present invention. FIG. 16 is a plan view showing a semiconductor device according to another embodiment of the present invention, and FIG. 17 is a plan view showing a semiconductor device according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Semiconductor chip, 2A ... Bip chip (semiconductor chip), 2B ... CMOS chip (semiconductor chip), 3 ... Insulator, 4 ... Inner lead (external electrode), 4A ... ... Inner lead for Vcc, 4B, ... Inner lead for Vss, 4C ... Wire connection point ... 5 ... Bonding pad (electrode), 5A ... Bonding pad (first electrode), 5B ... Bonding pad (second electrode), 6: coated wire, 6A: coated film, 6B: metal wire, 6C: metal ball, 7: bare wire, 8: package body, 8A: resin sealed Stopper, 9 ... outer lead,
10 Lead frame, 10A Guide hole, 10B Tab suspension lead, 10C Tab, 11 Wire bonding device, 11A First bonding mechanism, 11B Second bonding mechanism, 12 Transfer line, 13 Bonding head, 14 XY stage, 15 Bonding stage, 16 Control unit, 17A, 17B Bonding material, 18 Chip substrate, 19 Silicon oxide film, 20 ... PSG film, 21 ... Passivation film, 24 ... Vertical block, 25 ... Guide shaft, 26 ... Servo motor, 27 ... Ball screw mechanism, 28 ...
... Rotating shaft, 30 ... Bonding arm, 32 ... Elastic means, 33 ... Bonding tool, 34 ... Ultrasonic oscillator,
35 …… Wire spool, 35A …… Spool holder, 35B…
… Rotating shaft, 36 …… Airbag tensioner, 36A …… Guide plate, 36B …… Protrusion, 37 …… Sprocket, 38 …… Clamper, 38A …… Clamp tip, 40 …… Arc generator, 41 …… Electric torch , 42 ... fluid supply pipe, 43 ... adapter, 44 ... fluid outlet, 45 ... spacer, 47 ... cover, 48 ... tool insertion port, 50 ... suction device, 51 ... suction pipe, 52 ... fluid spray nozzle, 53 ... clamping member, 54 ... support member, 55 ... crankshaft, 56 ... drive source, 57 ... shaft, 58 ... fluid spray device, 60 ... cooling device, 61 ... … Flow meter, 62… Fluid transfer pipe, 63… Heat insulation material, Gs… Current eliminator, CGs… Cooling fluid, r… Uneven surface, α… Wire passage space, l ₁ … Short distance, l ₂ …… Long distance.

Claims (10)

(57) [Claims] 1. A plurality of wires for connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode, wherein a part of the wires is covered with an insulating coating film. 2. A semiconductor device of a resin-encapsulated type formed, wherein the wire straddling a lead disposed above the semiconductor chip is formed by the covering wire. 2. The semiconductor device according to claim 1, wherein said leads are leads corresponding to Vss to Vcc. 3. An electrode formed on a semiconductor chip is alternately arranged in a zigzag pattern at least along one side edge of the semiconductor chip.
The electrodes of the inner row and the outer row of the semiconductor chip are arranged in a row, and the external electrodes arranged along one side edge of the semiconductor chip and corresponding to the outside of the semiconductor chip are connected by wires, respectively. Semiconductor device,
A wire connecting the inner row of electrodes and the external electrode is formed by a coated wire coated with an insulating coating film, and the other wires are formed by bare wires not coated with an insulating coating film. A semiconductor device characterized by being formed. 4. An electrode formed on a semiconductor chip is disposed along at least one side edge of the semiconductor chip, and corresponding to each electrode of the semiconductor chip, an electrode is formed along one side edge of the semiconductor chip. The tips of the external electrodes arranged on the semiconductor chip are alternately arranged along one side edge of the semiconductor chip outside in a staggered manner, and the electrodes of the semiconductor chip and the tips of the external electrodes are connected by wires. The device, wherein, among the wires, a long-distance wire is formed by a coated wire coated with an insulating coating, and a short-distance wire is formed by a bare wire not coated with an insulating coating. A semiconductor device characterized by being formed. 5. The first resin sealed in a single resin sealing body.
A semiconductor device comprising a semiconductor chip and a second semiconductor chip, wherein a first electrode disposed along one side edge of the first semiconductor chip is opposed to the first electrode at a predetermined interval. And a second electrode disposed along one side edge of the second semiconductor chip by a wire, wherein one of the wires adjacent to each other is an insulating coating film. A semiconductor device characterized by being formed by a covered wire covered and the other by a bare wire not covered with an insulating covering film. 6. A plurality of wires for connecting an electrode formed on a semiconductor chip mounted on a tab and an external electrode corresponding to the electrode are partially covered with an insulating coating film. A resin-sealed semiconductor device formed by a covered wire, wherein the wire straddling a tab suspension lead is formed by the covered wire. 7. A plurality of wires connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode are formed by a covered wire in which some of the wires are covered with an insulating covering film. Wherein a wire connecting an electrode disposed on one side of the semiconductor chip and an external electrode disposed on the outside of the other side of the semiconductor chip comprises a wire. A semiconductor device comprising a covered wire. 8. A wire connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode is covered with a coating wire covered with an insulating coating film and an insulating coating film. A wire bonding method for a semiconductor device formed by using no bare wires, wherein the bonding process of the covering wire is performed after the bonding process of the bare wires. 9. A wire connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode is covered with a coating wire coated with an insulating coating film and an insulating coating film. What is claimed is: 1. A wire bonding apparatus for a semiconductor device, comprising: a bare wire; and a bonding step of the covered wire after the bonding step of the bare wire. 10. A wire connecting an electrode formed on a semiconductor chip and an external electrode corresponding to the electrode is not covered with a coated wire covered with an insulating coating film and not covered with an insulating coating film. A method of manufacturing a semiconductor device formed by bare wires, wherein after the bare wire bonding step, the covering wire bonding step is performed, and then the semiconductor chip, the electrodes, the external electrodes, and the wires are connected to each other. A method for manufacturing a semiconductor device, comprising manufacturing a semiconductor device by resin sealing.