JP4530230B2 - Wire bonding method and LED print head manufacturing method - Google Patents

Description

The present invention relates to a method for wire bonding a substrate pad formed on a substrate and an element pad formed on an electronic component mounted on the substrate, and a method for manufacturing an LED print head.

  2. Description of the Related Art Conventionally, a wire bonding method in which an electrode of a semiconductor element and an electrode of a substrate are connected to each other with a wire having a diameter of 10 to 150 μm formed of gold, copper or the like has been performed.

  In this wire bonding method, a wire protruding from the tip of a capillary through a through hole formed at the center of a movable capillary is connected to one electrode by a thermocompression bonding method using ultrasonic waves, and then the wire is connected from the through hole. This refers to a method in which the capillary is moved to the other electrode while being pulled out, the wire and the capillary are pressed against the other electrode, the wire is connected to the electrode by an ultrasonic thermocompression bonding method, and the wire is cut at the same time (see, for example, Patent Document 1) ).

JP-A-10-125707

Wherein the wire bonding how, after connecting the wire with ultrasonic thermocompression bonding method using a capillary element pads formed on the electronic component, the capillary is moved while pulling the wire, substrate pads formed on the substrate The capillary was pressed onto the wire and the wire was connected by the ultrasonic thermocompression bonding method, and at the same time, the wire was cut.

  In this case, since the thickness of the metal layer of the substrate pad is large, even if the metal debris of the substrate pad is deposited on the tip of the capillary, there is not much trouble in connecting the wire to the substrate pad.

  For example, the substrate pad has three metal layers (a layer mainly composed of copper having a thickness of about 15 μm and a layer mainly composed of nickel having a thickness of about 4 μm) on a base substrate mainly composed of glass epoxy. , 0.03 to 0.5 μm of gold as a main component), and has a metal layer thickness of about 20 μm.

  In this case, since the metal residue adhering to and depositing on the tip of the capillary is about 1 μm, the metal layer constituting the substrate pad is sufficiently thick even if the metal residue of the substrate pad adheres to the tip of the capillary. Then, the capillary with the metal residue attached can be pressed against the substrate pad to connect the wire to the substrate pad and to cut the wire.

  That is, when the capillary is pressed against the substrate pad, the deposited metal debris sinks into the metal layer, so that the connection of the wire to the substrate pad and the cutting of the wire can be performed without any problem. Further, when the deposited metal debris sinks into the metal layer, the metal debris remains in the metal layer and the metal debris peels from the capillary, so that subsequent wire bonding can be performed without any problem.

  However, when wire bonding is performed in the order of the element pad → the substrate pad, the wire is positioned above the element pad while drawing a large arc.

  Then, when the electronic component is a light emitting element or a light receiving element, the light hits the wire, the light reflected from the wire becomes stray light, the stray light enters the light emitted from the light emitting element, and the light emitting element transmits information. Or stray light enters the light incident on the light receiving element and adversely affects information obtained by the light receiving element.

  In order to solve such a problem, it is an effective means to perform wire bonding in the order of substrate pad → element pad. That is, after a wire is connected to a substrate pad formed on the substrate using a thermocompression bonding method using ultrasonic waves, the capillary is moved while the wire is pulled out, and the capillary is pressed against the element pad formed on the electronic component. Are connected by ultrasonic thermocompression bonding, and the wire is cut at the same time.

  With such a wire bonding method, since the arc of the wire located above the electronic component can be reduced, incident or emitted light can be prevented from hitting the wire.

  However, since the element pad is composed of a thin (eg, about 1 μm) metal film formed on a semiconductor substrate (eg, gallium arsenide, silicon, etc.) that constitutes an electronic component, the metal attached to the tip of the capillary If the residue is left as it is, the metal residue contacts the element pad, and thus a phenomenon that the capillary cannot be sufficiently pressed against the element pad occurs.

  For this reason, when wire bonding is performed in the order of the substrate pad → the element pad, new problems such as poor connection of the wire to the element pad and defective cutting of the wire occur.

The present invention has been made to solve such a problem, and even if metal debris is deposited on the tip of the capillary by wire bonding in the order of the substrate pad → the element pad, problems such as poor connection and disconnection are caused. and to provide a manufacturing method of a wire bonding method and the LED print head that does not cause.

  In the present invention, in the case where a dummy pad is formed in addition to a plurality of substrate pads, the substrate includes a plurality of substrate pads formed on the substrate and a plurality of substrate pads formed on the surface of the electronic component mounted on the substrate. The present invention relates to a method for continuously wire-bonding the element pads to each other with a capillary.

(1) When a voltage is applied between the wire protruding from the tip of the capillary and a torch described later, a spark is generated, and the wire is melted by the heat to form a ball. The ball is pressed against the substrate pad by the capillary, and a wire is connected to the substrate pad.

(2) After that, while pulling the wire from the capillary, move the capillary to the desired position, press the wire against the element pad by the capillary, connect the wire to the element pad, and simultaneously press the capillary against the element pad to cut the wire To do.

  The series of operations (1) and (2) described above is performed a plurality of times. For example, if the series of operations is performed three times, (1) → (2) → (1) → (2) → (1) → (2). As described above, when the above-described series of operations is performed a plurality of times, the metal residue constituting the element pad adheres to and accumulates on the tip of the capillary.

  In order to remove the deposited metal residue from the tip of the capillary, the following operation is performed. That is, (3) A torch described later is brought close to a wire protruding from the tip of the capillary, and a voltage is applied by the torch to generate sparks. Then, the wire protruding from the tip of the capillary is melted by the heat and becomes a ball. This ball is pressed against the dummy pad by the capillary and a wire is connected to the dummy pad (ultrasonic & thermocompression bonding).

  (4) When the wire is pulled out from the tip of the capillary, the capillary is slightly moved on the dummy pad, and the wire is pressed against the dummy pad again by the capillary to connect the wire to the dummy pad (ultrasonic & thermocompression bonding). At the same time, the capillary is pressed against the dummy pad to cut the wire.

  That is, by performing the series of operations (3) and (4) described above on the dummy pad provided on the substrate, the capillary is pressed against the dummy pad having a metal layer thicker than the element pad, Since the deposited metal debris sinks into the thick metal layer, the metal debris deposited at the tip of the capillary is removed at that time. The removed metal residue remains on the dummy pad, but the function of the substrate is not affected by the metal residue.

  The dummy pad refers to a pad having the same metal layer thickness as the substrate pad. The dummy pad may be an independent pad that is not electrically connected to the substrate pad formed on the substrate, or may be a part of the substrate pad. Further, the dummy pad may be a thickened wiring pattern for connecting the substrate pads formed on the substrate.

  By the wire bonding method described above, the pads (element pads) formed on the surface of the electronic component (semiconductor element) mounted on the substrate and the pads (substrate pad) formed on the substrate are continuously connected without replacing the capillary. Thus, wire bonding can be performed.

  The capillary is preferably coated with a diamond-like hard carbon film. Here, the diamond-like hard carbon film refers to a surface film mainly composed of carbon, such as DLC (diamond-like carbon) coating, TAC (tetrahedral amorphous carbon), or the like.

  Thus, by applying a diamond-like carbon hard film to the tip of the capillary, the peelability is improved, and not only the metal residue attached to the tip of the capillary is easily removed, but also the wear of the capillary itself is reduced. Therefore, the life of the capillary can be extended.

  The electronic component is a light emitting element, and a light emitting portion may be formed in the vicinity of an element pad formed on the surface of the electronic component. For example, the electronic component may be an LED array.

  In the case where the electronic component is a light emitting element such as an LED array, there is a problem that light is reflected on the wire when electrical conduction is achieved by wire bonding. However, the wire bonding method according to the present invention has such a problem. Does not occur.

  This is because the series of operations (1) → (2) described above involves wire bonding in the order of substrate pad → element pad, so the length of the wire positioned above the light emitting element such as the LED array is shortened ( This is because the wire arc can be reduced.

  For this reason, since the light emitted from the light emitting element does not hit the wire, the light reflected by the wire does not enter the information emitted as light from the light emitting element as stray light.

  Further, the electronic component is a light receiving element, and a light receiving portion may be formed in the vicinity of an element pad formed on the surface of the electronic component.

  This is because the series of operations (1) → (2) described above are performed in the order of wire bonding in the order of the substrate pad → element pad, so that the length of the wire positioned above the light receiving element is shortened as described above ( This is because the wire arc can be reduced.

  For this reason, since the light incident on the light receiving element does not hit the wire, the light reflected on the wire does not enter the information that enters the light receiving element as stray light.

  The dummy pad may be formed of a metal mainly composed of gold, and the element pad may be formed of a metal mainly composed of aluminum. The substrate pad may also be formed of a metal whose main component is gold.

  In this case, by repeating the series of wire bonding described in (1) and (2) above, an aluminum metal residue is deposited on the tip of the capillary.

  However, by performing the above-described series of operations (3) and (4) one or more times on the dummy pad provided on the substrate, the capillary has a metal layer more than the element pad when cutting the wire. Pressed against a thick dummy pad.

  Then, at that time, the metal debris mainly composed of aluminum deposited on the tip of the capillary sinks into the metal layer of the dummy pad, and at that time, an alloy is formed with the gold constituting the dummy pad. Therefore, when the operation (4) is performed, the metal residue remains on the dummy pad, and the metal residue is removed from the tip of the capillary.

Wire bonding method described above can be utilized as a method for manufacturing an LED print head.

That is, when a dummy pad is formed in addition to a plurality of substrate pads on a substrate fixed to a base formed of aluminum, resin, etc., the substrate is mounted on the substrate and the plurality of substrate pads formed on the substrate. and a plurality of elements pad formed on the surface of the LED array by wire bonding by capillary was, kill LED printhead manufacturing.

(5) When a voltage is applied between the wire protruding from the tip of the capillary and a torch described later, a spark is generated, and the wire is melted by the heat to form a ball. The ball is pressed against the substrate pad by a capillary, and a wire is connected to the substrate pad (ultrasonic & thermocompression bonding).

(6) Thereafter, the capillary is moved to a desired position while pulling the wire from the capillary, and the wire is pressed against the element pad by the capillary to connect the wire to the element pad (ultrasonic & thermocompression bonding). Press the pad to cut the wire.

  The series of operations (5) and (6) described above is performed a plurality of times when the LED print head base is manufactured. For example, if the series of operations is four times, (5) → (6) → (5) → (6) → (5) → (6) → (5) → (6).

  As described above, when the series of operations (5) and (6) described above is performed a plurality of times, the metal residue constituting the element pad adheres to the tip of the capillary and is deposited.

  The following operation is performed to remove metal debris deposited on the tip of the capillary. That is, (7) A torch described later is brought close to a wire protruding from the tip of the capillary, and a voltage is applied by this torch to generate sparks.

  Then, the wire protruding from the tip of the capillary is melted by the heat and becomes a ball. This ball is pressed against the dummy pad by a capillary and a wire is connected to the dummy pad (ultrasonic & thermocompression bonding).

  (8) When the wire is pulled out from the tip of the capillary, the capillary is moved slightly on the dummy pad, and the wire is pressed against the dummy pad again by the capillary to connect the wire to the dummy pad (ultrasonic & thermocompression bonding). At the same time, the capillary is pressed against the dummy pad to cut the wire.

  That is, by performing the series of operations (7) and (8) one or more times on the dummy pad provided on the substrate, the tip of the capillary is sufficiently large for the dummy pad having a metal layer thicker than the element pad. In this case, the metal residue deposited on the tip of the capillary is removed.

  For this reason, since it becomes possible to wire-bond continuously, without replacing | exchanging a capillary, it becomes possible to manufacture the base for LED print heads continuously.

  Further, a diamond-like hard carbon film may be applied to the surface of the tip of the capillary. Since the releasability is improved by applying the diamond-like carbon hard film, it is easy to remove the metal residue from the tip of the capillary, and the life of the capillary can be extended.

Furthermore, the dummy pad may be formed of a metal whose main component is gold, and the element pad formed on the surface of the LED array may be formed of a metal whose main component is aluminum. The substrate pad may also be formed of a metal whose main component is gold.
The dummy pad may be an independent pad that is not electrically connected to the substrate pad formed on the substrate, or may be a part of the substrate pad. Further, the dummy pad may be a thickened wiring pattern for connecting the substrate pads formed on the substrate.

  When the operations (5) and (6) described above are performed continuously, an aluminum metal residue is deposited on the tip of the capillary.

  However, by performing the above-described series of operations (7) and (8) in the dummy pad provided on the substrate, the tip of the capillary is a dummy pad whose main component is gold whose metal layer is thicker than the element pad. At that time, the metal debris mainly composed of aluminum deposited on the tip of the capillary is removed.

  In other words, the aluminum metal residue adhering to and deposited on the tip of the capillary is infiltrated into the metal layer constituting the dummy pad by the capillary. At this time, the metal residue aluminum and the gold constituting the dummy pad are alloyed. As a result, the metal residue adhered and deposited on the tip of the capillary is left on the dummy pad.

  For this reason, the LED print head base can be continuously produced by the method for manufacturing an LED print head base according to the present invention without causing a problem of metal debris deposited on the tip of the capillary.

  According to the present invention, even if the metal debris constituting the pad adheres to and accumulates on the tip of the capillary, the metal debris can be easily removed, so that the wire bonding can be continuously performed without replacing the capillary for a long period of time. There is an effect that can be done.

  Hereinafter, the present invention will be described in detail using examples.

A first embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side sectional view of a capillary. 2 to 4 are side views of the capillary. 5 to 14 are schematic views for explaining a wire bonding method according to the present invention.

5 to 9 are views of the substrate as viewed from the side, and the dummy pad at the end of the substrate should be illustrated, but the dummy pad is illustrated for easy understanding. Absent.
Moreover, although the wire 6 is a thin conducting wire having a diameter of about 10 to 150 μm, the wire 6 is shown thick in each figure for easy understanding.

(Capillary)
As shown in FIG. 1, the capillary 1 used in the present invention has a through hole 2 for supplying a wire, which will be described later, at the center. As the material of the capillary, ceramic, ruby, zirconium oxide or the like can be used.

(Wire bonding method)
Next, the wire bonding method according to the present invention will be described. Since the wire bonding device may be a known device that is commercially available, the description of devices other than the capillary will be omitted for simplicity of explanation.

  First, as shown in FIG. 2, a predetermined amount of wire 6 is supplied from the tip 3 of the capillary 1. Then, as shown in FIG. 3, the torch 7 constituting a part of the wire bonding apparatus is positioned in the vicinity of the wire 6 protruding from the tip 3 of the capillary 1, and a voltage is applied between the wire 6 and the torch 7. . The resulting spark melts the wire 6 protruding from the tip 3 of the capillary 1 to form a ball 8 as shown in FIG.

  FIG. 5 is a schematic view of the substrate 9 on which the substrate pad 12 is formed and the electronic component 10 is mounted as viewed from the side. As shown in FIG. 5, the capillary 1 on which the ball 8 is formed is moved directly above the substrate pad 12 using a wire bonding apparatus (not shown).

  Then, as shown in FIG. 6, the capillary 1 is lowered using a wire bonding apparatus (not shown), the ball 8 melted by the capillary 1 is pressed against the substrate pad 12, and the wire 6 and the substrate pad 12 are thermocompression bonded together with ultrasonic waves. Connect by method.

  Thereafter, as shown in FIG. 7, the wire 6 is moved toward the element pad 11 of the electronic component 10 while being pulled out from the tip 3 of the capillary 1 using a wire bonding apparatus (not shown).

  8 and 9, the capillary 1 is pressed against the element pad 11 by using a wire bonding apparatus (not shown), and the wire 6 is connected to the element pad 11 by the ultrasonic thermocompression bonding method. 6 is cut.

By performing the series of operations described above a plurality of times, the plurality of substrate pads 12 and the plurality of element pads 11 can be electrically connected by the wires 6.
However, the aluminum metal debris constituting the metal layer of the element pad adheres to the tip 3 of the capillary 1 and is deposited.

Therefore, in order to remove the metal residue deposited on the tip 3 of the capillary 1, the following operation is performed.
That is, as shown in FIG. 3, the torch 7 is positioned as shown in FIG. 4 in the vicinity of a predetermined amount of the wire 6 protruding from the tip 3 of the capillary 1, and a voltage is applied between the wire 6 and the torch 7. . Then, a spark is generated, and a ball 8 is formed at the tip 3 of the capillary 1 as shown in FIG.

  Thereafter, as shown in FIG. 10, the capillary 1 is moved onto a dummy pad 15 provided on another location (for example, an end portion of the substrate 9) of the substrate 9 where the electronic component 10 of the substrate 9 is not mounted.

  Then, as shown in FIG. 11, the capillary 1 is lowered using a wire bonding apparatus (not shown), the ball 8 melted by the capillary 1 is pressed against the dummy pad 15, and the wire 6 and the dummy pad 15 are combined with ultrasonic thermocompression bonding. Connect by method.

Thereafter, as shown in FIG. 12, the capillary 1 is moved toward another place of the dummy pad 15 while pulling the wire 6 from the tip 3 of the capillary 1 using a wire bonding apparatus (not shown).
Then, as shown in FIGS. 13 and 14, the capillary 1 is pressed against the dummy pad 15 using a wire bonding apparatus (not shown), and the wire 6 is connected to the dummy pad 15 by the ultrasonic thermocompression bonding method. 6 is cut.

  The dummy pad 15 formed on the substrate 9 has a metal layer (for example, 20 μm) thicker than a metal layer (for example, 1 μm) of the element pad. Even if it is done, it can be pressed sufficiently.

That is, the tip of the metal scrap capillary 1, since it is possible to buried in the dummy pad 15, when pressed against the capillary 1 to the dummy pad 15, and the metal debris deposited on the tip end of the capillary 1, the dummy pad 15 Alloys can be made between the metals that make up

  As a result, the metal residue deposited at the tip of the capillary 1 remains on the dummy pad 15, so that the metal residue can be removed from the tip 3 of the capillary 1.

  In this way, by performing a wire bonding operation on the dummy pad 15 whose main component is gold, which is easy to form an alloy with aluminum, which is a metal constituting the element pad 11, a metal residue (aluminum of aluminum) adhering to the tip 3 of the capillary 1 is obtained. Can be removed.

  As described above, even when the element pad 11 of the electronic component 10 is made of a metal having low hardness such as aluminum, the element pad 11 is formed of a metal that easily forms an alloy with the metal that forms the element pad 11. By performing the wire bonding operation on the dummy pad, the metal residue adhering / depositing on the capillary 1 can be automatically peeled / removed, so that the wire bonding operation can be continued continuously without maintenance of the capillary 1. it can.

Another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 15 is a side view of the LED print head. FIG. 16 is a plan view of an LED print head base in the LED print head shown in FIG. FIG. 17 is an enlarged view of the BB cross section of the LED print head base shown in FIG.
In addition, about the part same as the part demonstrated in Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the second embodiment, the wire bonding method described in the first embodiment is applied to manufacture of an LED print head base.

  As shown in FIG. 15, the LED print head includes an LED print head base 24 in which a long metal shaft 19 and a long substrate 9 are integrally molded with a resin 18, and a cover 21 to which a lens array 22 is fixed. Consists of.

  As shown in FIG. 16, a plurality of LED arrays 20 are mounted on the substrate 9 of the LED print head base 24 in a zigzag shape in the longitudinal direction, and a plurality of unillustrated substrate pads are formed in the zigzag substrate pad forming area 23. The substrate pad is formed.

A plurality of light emitting portions and a plurality of element pads are formed on the surface (upper surface) of the LED array 20, and the substrate 9 and the LED array are bonded by wire bonding the plurality of element pads and the plurality of substrate pads. 20 electrical continuity is realized.

17, Ru FIG der an enlarged base section B-B for the LED print head shown in FIG. 16. The element pads 11 of the LED array 20 mounted on the substrate 9 and the substrate pads 12 formed on the substrate 9 can be wire-connected by the wire bonding method described in the first embodiment.

That is, first, among the wire bonding methods shown in the first embodiment, the wire bonding between the substrate pad 12 and the element pad 11 is performed on all 56 LED arrays 20. After that, as shown in FIG. 16, the wire bonding shown in the first embodiment is performed one or more times on the dummy pad 15 provided at the end of the substrate 9.

  With this LED print head base manufacturing method, the metal residue of the element pad 11 of the LED array 20 attached to the capillary 1 can be removed from the dummy pad 15 each time the LED print head base is manufactured. The base for the LED print head can be continuously manufactured without maintaining 1.

  In the above-described method for manufacturing the LED print head base, the method of wire bonding for removing metal debris in the dummy pad after wire bonding of all LED arrays has been described. Each time the wire bonding of the plurality of element pads and the plurality of substrate pads corresponding to the plurality of element pads is completed, wire bonding for removing metal debris may be performed with a dummy pad.

  In the second embodiment, the dummy pad is made of a metal whose main component is gold, and the element pad is made of a metal whose main component is aluminum.

Another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 18 is a side view of the capillary, and FIG. 19 is an enlarged view of the capillary shown in FIG. 18 as viewed from below (direction A).
In addition, about the part same as the part demonstrated in Example 1 and Example 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The only difference from the first and second embodiments of the optical module according to this embodiment is that a diamond-like carbon hard coating 5 is applied to the tip 4 of the capillary 1.

  The diamond-like hard carbon film refers to a surface film mainly composed of carbon such as DLC (diamond-like carbon), TAC (tetrahedral amorphous carbon), or the like.

  By applying such a coating to the surface of the tip portion 4 of the capillary made of ceramic, not only the life of the capillary 4 is lengthened, but also metal debris is difficult to adhere to the tip 3 (tip surface 14) of the capillary 4. The peelability of the metal residue adhering to the tip 3 (tip surface 14) is improved.

  Therefore, in Example 1 or Example 2, by applying a diamond-like hard carbon film to the tip 4 of the capillary 4, the frequency of wire bonding for removing metal debris from the dummy pad 15 can be reduced. The wire bonding method described in Example 1 and the method for manufacturing the LED print head base described in Example 2 can be performed more continuously.

  The above-described embodiments are illustrated for illustrative purposes and are not intended to limit the present invention. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions are possible without departing from the technical idea of the present invention.

  In the above-described embodiments, the element pad mainly composed of aluminum and the substrate pad and dummy pad mainly composed of gold are used. However, the metal constituting the element pad and the metal constituting the dummy pad are heated. It is sufficient that the alloy is easily formed by ultrasonic vibration or the like, and the metal constituting the pad is not limited to aluminum and gold.

  In the above-described embodiment, the substrate pad and the dummy pad are made of the same material, but may be made of different materials.

In the above-described embodiments, the dummy pad is described as being independent of the substrate pad. However, the present invention is not limited to this, and a part of the substrate pad 12 may be used as the dummy pad.
That is, as shown in FIG. 20, an end portion that is an unused portion of the substrate pad 12 as a power supply line on which a plurality of LED arrays 20 are mounted may be used as the dummy pad 15.

Further, the width of a part of the wiring pattern connected to the substrate pad formed on the substrate may be widened, and the wiring pattern having the wide width may be used as the dummy pad.
That is, as shown in FIG. 21, in the middle of the wiring pattern 25 connected to the substrate pad 12, a portion where the width of the wiring pattern 25 is widened may be formed and used as a dummy pad.

Further, after wire bonding is repeated in the order of the substrate pad → element pad, wire bonding may be performed in the order of element pad → substrate pad in order to remove the metal residue adhering to and depositing on the tip of the capillary.
Even in this case, the metal residue adhering to the tip of the capillary sinks into the thick metal layer of the substrate pad, so that the metal residue can be removed from the tip of the capillary as described above.

The present invention is applied to a manufacturing method of a wire bonding method and the LED print head.

(Example 1) which is side sectional drawing of a capillary (Example 1) which is a side view of a capillary (Example 1) which is a side view of a capillary (Example 1) which is a side view of a capillary It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). It is a schematic diagram for demonstrating the wire bonding method concerning this invention (Example 1). (Example 2) which is a side view of a LED print head. (Example 2) which is a top view of the base for LED print heads in an LED print head (Example 2) which is an enlarged view of the base cross section for LED print heads. (Example 3) which is a side view of a capillary (Example 3) which is an enlarged view when seeing a capillary from the downward direction (A direction) It is a perspective view of the board | substrate for demonstrating the wire bonding method concerning this invention. It is a perspective view of the board | substrate for demonstrating the wire bonding method concerning this invention.

DESCRIPTION OF SYMBOLS 1 Capillary 2 Through-hole 3 Tip 4 Tip 5 Diamond-like carbon hard film 6 Wire 9 Substrate 10 Electronic component 11 Element pad 12 Substrate pad 13 Light-emitting part 15 Dummy pad 24 LED print head base 25 Wiring pattern

Claims (4)

A plurality of substrate pads formed on the substrate;
In a wire bonding method in which a plurality of element pads formed on the surface of an electronic component mounted on the substrate and having a metal layer thinner than the substrate pad are connected by a wire protruding from the tip of a capillary,
The wire protruding from the tip of the capillary is pressed against the substrate pad by the capillary to connect the wire to the substrate pad,
Move the capillary while pulling out the wire,
After performing a series of operations for cutting the wire at the same time as connecting the wire to the element pad by pressing the wire against the element pad by the capillary,
The wire protruding from the tip of the capillary, is formed on the substrate by the capillary, the wire connected to the dummy pad thickness of the metal layer is pressed against the same dummy pad and the substrate pads,
Move the capillary while pulling out the wire,
The wire bonding method characterized by pressing the wire against the dummy pad by the capillary to connect the wire to the dummy pad and simultaneously cutting the wire   The wire bonding method according to claim 1, wherein the dummy pad is a part of a substrate pad or a wiring pattern connected to the substrate pad. A substrate on which a plurality of LED arrays are mounted;
A base to which the substrate is fixed;
In a method of manufacturing an LED print head comprising a cover having a lens array fixed to the base,
The substrate is
A plurality of substrate pads formed on the substrate;
When wire bonding a plurality of element pads formed on the surface of the LED array mounted on the substrate and having a metal layer thinner than the substrate pad with a capillary,
The wire protruding from the tip of the capillary is pressed against the substrate pad by the capillary to connect the wire to the substrate pad,
Move the capillary while pulling out the wire,
After performing a series of operations for cutting the wire at the same time as connecting the wire to the element pad by pressing the wire against the element pad by the capillary,
The wire protruding from the tip of the capillary, is formed on the substrate by the capillary, the thickness of the metal layer is pressed against the same the dummy pad and the substrate pads to connect the wires to the dummy pad,
Move the capillary while pulling out the wire,
A method of manufacturing an LED print head, wherein the wire is pressed against the dummy pad by the capillary to connect the wire to the dummy pad and simultaneously cut the wire. 4. The method of manufacturing an LED print head according to claim 3, wherein the dummy pad is a part of a substrate pad or a wiring pattern connected to the substrate pad.

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