Heating chip unit

Abstract

The present invention is a heater tip unit in which a temperature measurement section of a temperature sensor can satisfactorily be caused to come into contact with a location at which a heater tip is affixed. Specifically, the present invention is a heater tip unit 1 in which a thermocouple 3 is attached to a plate-shaped heater tip 2 for thermocompression bonding of a terminal conductive wire to a terminal member, wherein: the heater tip 2 is provided with an iron section 6 in which an iron body 11 is provided with an iron tip section 13 which abuts the terminal conductive wire, a pair of connection arms 7 which are provided extending, from left and right end sections of the iron body 11, upward and away from each other and which heat the iron section 6 by passing a current from a power source to the iron body 11, and a temperature measurement affixing section 35 which is provided to the iron section 6 and to which temperature measurement contacts 3a of the thermocouple 3 are affixed; the temperature measurement affixing section 35 is provided with a pair of affixing contact surfaces 35a which the temperature measurement contacts 3a contact; and the distance by which the affixing contact surfaces 35a are separated from each other is set so as to gradually expand moving upward from the iron section 6 side.

Description

Heater Tip Unit

[0001] The present invention relates to a heater chip unit for thermocompression bonding a terminal conductor to a terminal member.

[0002] A heater chip unit for thermocompression bonding is used in the process of thermocompression bonding a terminal wire to a terminal member, for example, in the process of thermocompression bonding a lead wire to a terminal portion of a core in the manufacture of electronic components such as chip inductors. Specifically, a heater chip unit is constructed by attaching a thermocouple as a temperature sensor to a heater tip whose iron portion heats up, and this heater chip unit is attached to a tool holder of a thermocompression bonding device. Then, the thermocompression bonding device is operated, and the terminal wire placed on the terminal member is rapidly heated while being pressed by the iron portion of the heater tip, thereby thermocompression bonding the terminal wire to the terminal member (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-284781

[0004] In the heater tip (heater tip unit) described in the above patent document, the thermocouple wire is passed through a through-hole in the heater tip, and arc welding is performed in this state to simultaneously form a temperature measuring junction (temperature measuring portion of the temperature sensor) and fasten (bond) the temperature measuring junction to the heater tip. However, poor welding can result in the temperature measuring junction not being formed and only the wire being bonded to the heater tip, resulting in poor yield. Therefore, it is preferable to form the temperature measuring junction in advance before fastening it to the heater tip, and then bring this temperature measuring junction (temperature measuring portion) into sufficient contact with the heater tip and fasten it in this state.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a heater chip unit that can bring the temperature measuring part of the temperature sensor into sufficient contact with the fastening point of the heater chip.

[0006] The present invention has been proposed to achieve the above-mentioned object, and is described in claim 1 as a heater chip unit having a temperature sensor attached to a plate-shaped heater chip for thermocompression bonding a terminal conductor to a terminal member, wherein the heater chip comprises: a soldering iron portion having a soldering iron tip portion on a soldering iron body that contacts the terminal conductor; a pair of connecting arms that extend upward from the left and right ends of the soldering iron body while being spaced apart from each other and that pass current from a power source to the soldering iron body to raise the temperature of the soldering iron portion; and a temperature measuring fastening portion that is provided on the soldering iron portion and to which a temperature measuring portion of a temperature sensor is fastened, wherein the temperature measuring fastening portion has a pair of fastening contact surfaces with which the temperature measuring portion comes into contact, and the heater chip unit is characterized in that the distance between the fastening contact surfaces is set to gradually increase as it moves upward from the soldering iron portion side.

[0007] A second aspect of the present invention is the heater chip unit according to the first aspect, characterized in that the fastening contact surface is configured as a flat surface, and the temperature measuring portion is configured as a spherical body.

[0008] The heater chip unit according to claim 3 is characterized in that the gap between the connecting arms serves as a conductor storage cavity, and the conductor of the temperature sensor is stored in the conductor storage cavity, and the fastening contact surface faces the end of the conductor storage cavity.

[0009] The heater chip unit according to claim 4 is characterized in that the heater chip has an oxidation-resistant coating layer formed on at least the surface of the soldering iron portion and the temperature-measuring fastening portion.

[0010] A fifth aspect of the present invention is the heater chip unit according to the fourth aspect, characterized in that an oxidation-resistant coating layer is formed on the surface of the temperature measuring part fastened to the temperature measuring fastening part.

[0011] A sixth aspect of the present invention is the heater chip unit according to the fourth or fifth aspect, characterized in that the oxidation-resistant coating layer is a nickel coating.

[0012] The present invention has the following excellent effects. According to the invention described in claim 1, the temperature-sensing fastening part has a pair of fastening contact surfaces with which the temperature-sensing part comes into contact, and the distance between the fastening contact surfaces is set to gradually increase as it moves upward from the soldering iron part side, so that the temperature-sensing part of the temperature sensor can be brought into sufficient contact with the temperature-sensing fastening part. Therefore, it is possible to configure a heater chip unit that allows good fastening of the temperature-sensing part to the heater chip and therefore good temperature measurement.

[0013] According to the invention of claim 2, since the fastening contact surface is configured as a flat surface and the temperature measuring part is configured as a spherical body, the temperature measuring part can easily make point contact with the fastening contact surface. Furthermore, when the temperature measuring part is pressed against the fastening contact surface, stress is easily concentrated, making it difficult for the temperature measuring part to float from the fastening contact surface. This allows for better fastening of the temperature measuring part to the heater tip, and ultimately allows for better temperature measurement of the heater tip.

[0014] According to the third aspect of the present invention, the gap between the connecting arms serves as a conductor storage cavity into which the conductor of the temperature sensor is stored, and the fastening contact surface faces the end of the conductor storage cavity, so that when the temperature sensor is inserted into the conductor storage cavity with the temperature measuring portion at the front, the temperature measuring portion can be easily brought into contact with the fastening contact surface. This allows for smooth preparation for fastening the temperature measuring portion of the temperature sensor to the temperature measuring fastening portion.

[0015] According to the fourth to sixth aspects of the present invention, oxidation of the surface can be suppressed even when heating and cooling are repeated, and durability can be improved.

[0016]

[0023] FIG. 1 is a perspective view of a heater chip unit.

[0024] FIG. 1 is an explanatory diagram of a heater chip, where (a) is a plan view, (b) is a front view, (c) is a bottom view, and (d) is a side view.

[0025] FIG. 2 is an explanatory diagram of a temperature-measuring fastening portion of the heater chip, where (a) is a front view and (b) is a cross-sectional view.

[0026] FIG. 3 is an explanatory diagram of a procedure for attaching a thermocouple to a heater chip, where (a) is the state before the thermocouple is inserted into the heater chip, (b) is the state after the thermocouple has been inserted into the heater chip, and (c) is the state after resin has been injected into the conductor accommodating cavity and the fastening recess as a conductor fastening portion.

[0027] FIG. 1 is a perspective view of a heater chip equipped with two soldering iron portions.

[0028] FIG. 2 is an explanatory diagram of a heater chip equipped with two soldering iron portions, where (a) is a plan view, (b) is a front view, (c) is a bottom view, and (d) is a side view.

[0017] An embodiment of the present invention will now be described with reference to the drawings. As shown in FIGS. 1 and 2 , a heater chip unit 1 includes a plate-shaped heater chip 2 for thermocompression bonding a terminal wire A to a terminal member B (see FIG. 2(d)), and a thermocouple 3 attached to the heater chip 2 as a temperature sensor. The heater chip 2 is formed by wire electric discharge machining of a plate of conductive material (tungsten, molybdenum, cemented carbide, etc.). As shown in FIG. 2 , the heater chip 2 includes a soldering iron portion 6 that forms the lower portion (the tip portion facing the workpiece (terminal wire A or terminal member B)) of the heater chip 2, and a pair of left and right connecting arms 7 that form the upper portion (base). When electricity is applied to the soldering iron portion 6 via the connecting arms 7, electrical resistance causes the soldering iron portion 6 to generate heat, and the temperature of the soldering iron portion 6 can be measured by the thermocouple 3.

[0018] The iron part 6 includes a horizontally elongated iron body 11 that connects the lower portions of the connecting arms 7. The width of the iron body 11 (the dimension along the horizontal direction in which the pair of connecting arms 7 are aligned) gradually narrows toward the bottom of the heater tip 2. A box-shaped iron tip 13 projects downward from the bottom of the iron body 11, which protrudes slightly downward. The bottom surface (front end surface) of the iron tip 13 serves as an iron tip surface 13a that can abut against the terminal conductor A. Furthermore, a substantially rectangular iron recess 15 is formed in the upper portion (connecting arm 7 side) of the iron body 11 opposite the iron tip 13. The temperature measuring junction (temperature measuring portion) 3a of the thermocouple 3 is secured within the iron recess 15. The structure for securing the temperature measuring junction 3a will be described in detail later.

[0019] The connecting arms 7 are vertically long components extending upward from the left and right ends of the iron body 11, and are provided spaced apart from each other. Furthermore, an attachment hole 17 for attaching to a tip holder (not shown) of a thermocompression bonding device penetrates the upper part (extended end) of the connecting arm 7 in the thickness direction of the heater tip 2, and an attachment bolt (not shown) is threaded through this attachment hole 17 into the tip holder, so that the heater tip unit 1 is attached to the tip holder with the iron tip 13 facing downward.

[0020] In the heater chip unit 1 attached to the chip holder, one connecting arm 7 is electrically connected to one end of a heater power supply (not shown) of the thermocompression bonding device, and the other connecting arm 7 is electrically connected to the other end of the heater power supply. When current flows from the power supply (heater power supply) to the heater chip 2, the current flows through the connecting arm 7 into the soldering iron body 11, causing the soldering iron body 11 to heat up due to electrical resistance within the soldering iron body 11, and this heat raises the temperature of the soldering iron tip 13. Furthermore, current flows within the soldering iron body 11 from one connecting arm 7 side to the other connecting arm 7 side. However, the cross-sectional area of ​​the constricted portion located at the corner of the soldering iron recess 15 along the current flow path is narrower than the cross-sectional area of ​​other portions, so the current density is highest at this constricted portion, and Joule heat is likely to be generated around this portion due to electrical resistance.

[0021] 1 and 2(d), the heater tip 2 has grooves 20 extending in the left-right direction (from one connecting arm 7 to the other connecting arm 7) on both the front and back surfaces of the heater tip 2 in a range from the lower part of the connecting arm 7 to the iron body 11, as gouges in the present invention, and the extension of these grooves 20 on the front and back forms thin-walled portions 21, and the iron tip 13 is configured to protrude below the thin-walled portions 21. In other words, the thin-walled portions 21 are formed at positions away from the iron tip 13 (more specifically, closer to the connecting arm 7 than the iron tip 13).

[0022] 2(d), the depth dimensions (dimension in the thickness direction of the heater tip 2) of the grooves 20 on the front and back are set to be the same, so that the centers of the connecting arm 7, the iron body 11 (thin portion 21), and the iron tip 13 in the thickness direction are positioned on the same plane, and the thickness of the iron tip 13 is set to be the same as the thickness of the connecting arm 7. Furthermore, the surfaces of the thin portions 21 that form the bottoms of the grooves 20 are set to be the side surfaces (front and back surfaces) of the iron body 11, the thickness of the iron body 11 (thickness of the thin portions 21) is thinner than the thickness of the connecting arm 7, and the cross-sectional area of ​​the iron body 11 (in other words, the cross-sectional area as a flow path for current) is set to be smaller than the cross-sectional area of ​​the connecting arm 7. The thickness t1 of the side of the iron body 11 is made thinner than the thickness t2 of the connecting arm 7 (more specifically, the thickness of the connecting arm 7 excluding the thin portion 21 (the thickness of the connecting arm 7 at the portion outside the thin portion 21)) (see Figures 1 and 2(d)).

[0023] Next, the thermocouple 3 attached to the heater tip 2 and the configuration on the heater tip 2 for attaching the thermocouple 3 will be described. As shown in Figures 1 and 3, the thermocouple 3 is formed by welding the tips of two types of elemental wires 25 together to form a spherical temperature-measuring junction (temperature-measuring portion) 3a, and each elemental wire 25 is coated with an electrically insulating elemental wire coating material 26, which is then bundled together with an outer coating material 27 to form a conductor 3b. In other words, the elemental wires 25 are included in the conductor 3b. Furthermore, the diameter of the temperature-measuring junction 3a and the wire diameter of the conductor 3b are each set smaller than the plate thickness of the heater tip 2.

[0024] In addition, in the heater tip 2, a storage location for the conductor 3b is provided in the gap between the connecting arms 7, and a fastening location for the temperature-measuring contact 3a is provided in the iron part 6. Specifically, as shown in Figures 1 and 2(a) and (b), the gap between the connecting arms 7 extending along the longitudinal direction of the connecting arms 7 is set as a conductor storage cavity 30 with an open upper end and an area (thickness, width) slightly larger than the diameter of the conductor 3b, and the conductor 3b (more specifically, the portion of the conductor 3b located near the temperature-measuring contact 3a) is stored in this conductor storage cavity 30 without protruding outward from either the front or back surfaces of the heater tip 2. The conductor 3b extends from an open opening 30a at the upper end of the conductor storage cavity 30, and the lower end of the conductor storage cavity 30 is expanded to communicate with the iron recess 15 (see Figure 1).

[0025] Furthermore, a part of the side of each connecting arm 7 facing the conductor storage cavity 30 is cut out to form a stop recess 31 that is connected to the conductor storage cavity 30, and each stop recess 31 and a part of the conductor storage cavity 30 (the part located between the stop recesses 31) are filled with resin such as ultraviolet curing resin or thermosetting resin and then hardened (solidified) to form a wire stop portion 32, which prevents the conductor 3b from shifting out of the conductor storage cavity 30 and protruding from the heater tip 2.

[0026] Furthermore, the tip recess 15 formed in the tip 6 has a temperature measuring fastening portion 35, to which the temperature measuring contact 3a of the thermocouple 3 is fastened, protruding toward the upper connecting arm 7 at a location facing the end (lower end) of the conductor storage cavity 30. As shown in Figure 3, the temperature measuring fastening portion 35 is a protrusion provided on the opposite side of the tip 13 across the tip 11, and is formed slightly smaller than the tip 13. Furthermore, the portion facing the conductor storage cavity 30 (the upper part of the temperature measuring fastening portion 35) has a pair of fastening contact surfaces 35a with which the temperature measuring contact 3a comes into contact, which face the end of the conductor storage cavity 30, and the spacing between the fastening contact surfaces 35a gradually increases as the distance from the tip 6 side increases toward the upper conductor storage cavity 30 side. By making each fastening contact surface 35a flat, a V-shaped recess 36 is formed in the upper part of the temperature measuring fastening portion 35 (the upper part on the side of the conductor storage space 30), and the temperature measuring contact 3a is received in this recess 36 and brought into contact with the fastening contact surface 35a, and in this state the temperature measuring contact 3a is fastened to the soldering iron portion 6 (temperature measuring fastening portion 35) by welding or the like.

[0027] Next, the procedure for fabricating the heater chip unit 1, particularly the procedure for attaching the thermocouple 3 to the heater chip 2, will be described. First, as shown in Figure 4(a), the heater chip 2 and thermocouple 3, which have been fabricated separately in advance, are arranged with the opening 30a of the conductor housing cavity 30 and the temperature-measuring junction 3a facing each other. The orientation of the heater chip 2 and thermocouple 3 is then set, and the temperature-measuring fastening portion 35, conductor housing cavity 30, temperature-measuring junction 3a, and conductor 3b are aligned in this order on a straight line. After the orientation of the heater chip 2 and thermocouple 3 is set, the thermocouple 3 is inserted into the opening 30a of the conductor housing cavity 30 of the heater chip 2, with the temperature-measuring junction 3a at the front. Then, the side of the connecting arm 7 acts as a guide, guiding the thermocouple 3 toward the soldering iron 6.

[0028] Furthermore, when the thermocouple 3 is inserted deeper, the temperature measuring contact 3a passes through the conductor storage cavity 30 and then enters the soldering iron recess 15, as shown in FIG. 4(b). As shown in FIG. 3(a), the soldering iron 6 has a temperature measuring fastening portion 35 at the location facing the lower end of the conductor storage cavity 30 (the open end on the soldering iron 6 side), and the V-shaped fastening contact surface 35a faces the end of the conductor storage cavity 30. Therefore, the temperature measuring contact 3a that enters the soldering iron recess 15 reaches the temperature measuring fastening portion 35 and makes contact with the fastening contact surface 35a. In this way, the temperature measuring contact 3a can be easily and reliably abutted against the fastening contact surface 35a (temperature measuring fastening portion 35). This allows for smooth preparation for fastening the temperature measuring contact 3a to the temperature measuring fastening portion 35.

[0029] The conducting wire 3b is then pressed toward the temperature-sensing fastening portion 35 to maintain contact with the fastening contact surface 35a of the temperature-sensing fastening portion 35, and in this state, the temperature-sensing fastening portion 35 and the fastening contact surface 35a are fastened (welded) together by laser welding. Specifically, a laser is irradiated onto the fastening contact surface 35a to heat it, and the temperature-sensing contact 3a is melted and fastened (welded) by the heat. At this time, as shown in FIG. 3( a), the distance between the fastening contact surfaces 35a in the temperature-sensing fastening portion 35 is set to gradually increase upward from the soldering iron portion 6 side, so that the temperature-sensing contact 3a can be brought into sufficient contact with the temperature-sensing fastening portion 35. Therefore, a heater chip unit 1 can be configured that allows good fastening of the temperature-sensing contact 3a to the heater chip 2 and, ultimately, good temperature measurement. Furthermore, since the fastening contact surface 35a is flat and the temperature measuring contact 3a is spherical, the temperature measuring contact 3a can easily come into point contact with the fastening contact surface 35a. Also, by pressing the temperature measuring contact 3a against the fastening contact surface 35a, stress is easily concentrated, making it difficult for the temperature measuring contact 3a to float from the fastening contact surface 35a. This allows the temperature measuring contact 3a to be more securely fastened to the heater tip 2, and ultimately allows for more efficient temperature measurement of the heater tip 2.

[0030] Once the temperature measuring contact 3a has been fastened to the temperature measuring fastening portion 35, as shown in Figure 4(c), a resin such as an ultraviolet curing resin or a thermosetting resin is injected into a part of the conductor storage cavity 30 (the part located between the fastening recesses 31) and each fastening recess 31 in an unhardened state (fluid state) to fill it, and then a resin hardening process such as ultraviolet irradiation or heating is performed to harden the resin to form the conductor fastening portion 32.

[0031] In the heater chip unit 1 configured by attaching the thermocouple 3 to the heater chip 2 in this manner, the conductor wire 3b of the thermocouple 3 is stored in the conductor storage cavity 30, so that the conductor wire 3b of the thermocouple 3 can be prevented from protruding from the range of the plate thickness of the heater chip 2. Therefore, when handling the heater chip unit 1, such as when installing it in a thermocompression bonding device, or when the heater chip unit 1 enters a work area, the conductor wire 3b is unlikely to be accidentally caught on, and the thermocouple 3 is unlikely to fall off from the heater chip 2. Furthermore, when multiple heater chip units 1 are to be bundled together for transportation (shipment) or storage, the heater chip units 1 can be stacked stably without any hindrance, allowing for smooth transportation and storage operations.

[0032] Furthermore, the conductor storage cavity 30 is provided with a conductor stopper 32, which prevents the stored conductor 3b from becoming detached from the conductor storage cavity 30. Furthermore, since the conductor stopper 32 is made of resin that has been injected into the conductor storage cavity 30 and then hardened, it is easy to fill the gap between the connecting arm 7 and the conductor 3b as the conductor stopper 32, thereby sufficiently securing the conductor 3b. Furthermore, since the conductor storage cavity 30 is provided with a stopper recess 31 that communicates with the conductor storage cavity 30 and the resin that forms the conductor stopper 32 has been injected into the conductor storage cavity 30 and the stopper recess 31 and then hardened, the conductor stopper 32 is less likely to become detached from the conductor storage cavity 30, which prevents the conductor 3b and the conductor stopper 32 from becoming detached from the conductor storage cavity 30.

[0033] To thermocompression bond the terminal wire A to the terminal member B using the heater chip unit 1, first, the heater chip unit 1 is mounted in the tip holder of the thermocompression bonding device with the tip 13 facing downward, and the thermocouple 3's lead wire 3b is connected to the thermocouple connection terminal (not shown) of the thermocompression bonding device. The terminal member B and the terminal wire A are then set in a work area (neither of which is shown) below the tip holder, and the terminal wire A is placed on top of the terminal member B. Once the terminal member B and the terminal wire A are set, the heater chip unit 1 is lowered together with the tip holder to press the tip 13 against the terminal wire A. Furthermore, current is applied to the heater chip 2 to heat the iron body 11, thermocompression bonding the terminal wire A to the terminal member B. The thermocouple 3 measures the temperature of the iron tip 6, and a control unit (not shown) of the thermocompression bonding device controls the current flow to the heater chip 2 and the temperature of the tip 13 based on this measurement.

[0034] Here, in the heater tip 2 that generates heat, the thickness of the soldering iron body 11 is set thinner than the thickness of the connecting arm 7, and the cross-sectional area of ​​the soldering iron body 11 is set smaller than the cross-sectional area of ​​the connecting arm 7. Therefore, even if the thickness of the heater tip 2 is increased, the problem of a decrease in current density in the soldering iron body 11 and insufficient heat generation can be prevented. Therefore, good heat generation efficiency can be easily achieved regardless of the thickness of the heater tip 2. Furthermore, an increase in the volume of the soldering iron body 11 and, therefore, its heat capacity can be avoided, facilitating rapid cooling of the soldering iron body 11 and the soldering iron tip 13. Furthermore, the groove 20 extends from the lower part of the connecting arm 7 to the soldering iron body 11 to form the thin-walled portion 21, and the surface of the thin-walled portion 21, which forms the bottom of the groove 20, forms the side surface of the soldering iron body 11. This makes it easy to realize a heater tip 2 structure in which the soldering iron body 11 is thinner than the connecting arm 7.

[0035] Furthermore, because the tip 13 protrudes below the thin portion 21, if foreign matter (such as the insulating coating of the terminal wire A) adheres to the tip 13 during the thermocompression bonding process, it can be easily removed by grinding the tip 13. Furthermore, sufficient grinding allowance can be secured at the tip of the tip 13, thereby extending the replacement cycle (service life) of the heater tip unit. Furthermore, by forming the thin portion 21 closer to the connecting arm 7 than the tip 13, the thickness of the side of the iron body 11 is thinner than the thickness of the connecting arm 7 excluding the thin portion 21. This prevents a decrease in current density in the iron body 11 while ensuring a sufficient thickness dimension at the tip of the tip 13. This allows for a wider range of sizes of workpieces (targets) that can be thermocompression bonded to the heater tip 2. Furthermore, since the thin-walled portion 21 is formed at a position away from the tip portion 13 and the thickness of the tip portion 13 is set to be the same as that of the connecting arm portion 7, there is no need to increase or decrease the thickness of the tip portion 13 relative to the thickness of the connecting arm portion 7, making it easy to manufacture the heater tip 2.

[0036] Furthermore, because the centers of the connecting arm 7, the iron body 11, and the iron tip 13 in the thickness direction are located on the same plane, bending moments are less likely to occur within the heater tip 2 during thermocompression bonding, preventing the disadvantage of excessive load being placed on the heater tip 2 and, ultimately, the disadvantage of the heater tip 2 being more susceptible to damage. Furthermore, because the thermocouple 3 is attached to the iron part 6 of the heater tip 2 as a temperature sensor, information on the temperature of the iron part 6 can be obtained and used to control the heat generation of the heater tip 2. Furthermore, the temperature sensor can be realized with a simple configuration.

[0037] In the above embodiment, the soldering iron body 11 is configured by extending the grooves 20 on both the front and back surfaces of the heater tip 2 to form the thin-walled portions 21. However, the present invention is not limited to this. Essentially, any configuration of the soldering iron body 11 may be provided on the heater tip 2 as long as the thickness of the soldering iron body 11 is thinner than the thickness of the connecting arm 7 and the cross-sectional area of ​​the soldering iron body 11 is smaller than the cross-sectional area of ​​the connecting arm 7. For example, the soldering iron body 11 may be configured by extending the grooves on either the front or back surface of the heater tip 2 to form the thin-walled portions 21. However, if the soldering iron body 11 is positioned unevenly on either the front or back surface of the heater tip 2, a bending moment will be generated within the heater tip 2 during the thermocompression bonding operation. Therefore, it is preferable to adopt a configuration in which the centers of the connecting arm 7, the soldering iron body 11, and the soldering iron tip 13 in the thickness direction are located on the same plane, i.e., the configuration of the above embodiment. It is only necessary for the soldering iron body 11 to be configured to include the portion with the highest electrical resistance (the portion that becomes the heat-generating portion). Therefore, the area where the thickness is reduced by the groove or the like may extend into the connecting arm portion 7, and does not necessarily have to be the entire area of ​​the iron body 11.

[0038] Although the thickness of the tip 13 and the connecting arm 7 are set to the same dimension, the present invention is not limited to this. For example, by reducing the thickness of the tip 13 to be thinner than the connecting arm 7, the degree of freedom in the thickness dimension of the tip 13 can be increased, making it easier to design a heater tip 2 that corresponds to the size of the workpiece (terminal member B, terminal conductor A) to be subjected to thermocompression bonding. Furthermore, as shown in FIG. 3 , the temperature-measuring fastening portion 35 is configured to be slightly smaller than the tip 13, but the present invention is not limited to this. For example, by making the volumes of the tip 13 and the temperature-measuring fastening portion 35 the same and setting them to avoid an extreme difference in the thermal capacity between the tip 13 and the temperature-measuring fastening portion 35, it is possible to synchronize the temperature change at the tip 13 and the temperature change at the temperature-measuring fastening portion 35, making it easier to manage the temperature of the tip 13 based on the temperature measurement at the temperature-measuring fastening portion 35.

[0039] Furthermore, while the fastening contact surface 35a of the temperature-measuring fastening portion 35 is flat, the present invention is not limited to this. In short, the fastening contact surface 35a may be curved as long as the distance between the fastening contact surfaces 35a gradually increases upward from the soldering iron portion 6. Furthermore, as long as the temperature-measuring contact (temperature-measuring portion) 3a can be sufficiently contacted with the fastening contact surface 35a, the temperature-measuring contact 3a is not limited to being spherical and may be formed into any shape. Furthermore, while the temperature-measuring contact 3a of the thermocouple 3 and the temperature-measuring fastening portion 35 are fastened by welding, the present invention is not limited to this. In short, as long as the temperature of the soldering iron portion 6 can be measured, the fastening method between the temperature-measuring contact 3a and the temperature-measuring fastening portion 35 is not important. For example, the temperature-measuring contact 3a and the temperature-measuring fastening portion 35 may be fastened using an adhesive (adhesive) with good thermal conductivity.

[0040] In the heater tip 2 of the above embodiment, the wire storage cavity 30 extends linearly along the longitudinal direction of the connecting arm 7, but the present invention is not limited to this. Essentially, any type of wire storage cavity 30 may be used as long as it is capable of storing the wire 3b of the thermocouple 3. For example, the wire storage cavity 30 may extend in a bent or curved shape. While UV-curable resin, thermosetting resin, or other resins are used as examples of the wire stopper 32 in the present invention, the present invention is not limited to this. Essentially, any type of wire stopper 32 may be used as long as it can stop the wire 3b stored in the wire storage cavity 30 and prevent it from falling out of the wire storage cavity 30. For example, a cap that fits onto the wire storage cavity 30 may be used as the wire stopper. Alternatively, a protrusion that is integrally molded on the connecting arm 7 and protrudes toward the wire storage cavity 30 may be used as the wire stopper.

[0041] Furthermore, although the retaining recess 31 communicating with the conductor storage cavity 30 is configured as a shallow notch in the side surface of the conductor storage cavity 30, the present invention is not limited to this. Essentially, any configuration of the retaining recess 31 may be adopted as long as the resin forming the conductor wire retainer 32 can be injected from the conductor wire storage cavity 30 into the retaining recess 31 and hardened. For example, groove-shaped retaining recesses may be formed on both the front and back surfaces of the connecting arm 7, and the ends of these retaining recesses may be connected to the conductor wire storage cavity 30 so that the resin (conductor wire retainer 32) can be injected from the conductor wire storage cavity 30 into the retaining recess.

[0042] Furthermore, in the above embodiment, the thermocouple 3 is exemplified as the temperature sensor of the present invention, and the temperature measuring junction 3a of the thermocouple 3 is exemplified as the temperature measuring portion of the present invention, but this is not limiting. In short, any type of temperature sensor may be adopted and attached to the heater tip 2 as long as it is capable of measuring the temperature of the soldering iron part 6 and is configured with a temperature measuring portion at the end of the conductor 3b.

[0043] In the above embodiment, the groove 20 is exemplified as the recessed portion of the present invention, but the present invention is not limited to this. The point is that the recessed portion may be configured in any manner as long as it extends in the direction from one connecting arm to the other, thereby forming a thin-walled portion in the heater tip. For example, the heater tip 2' of the second embodiment shown in Figures 5 and 6 is basically the same as the above embodiment (first embodiment), but differs in that recessed portions are formed not only on both surfaces of the heater tip 2' but also in the middle portion in the plate thickness direction of the heater tip 2', thereby bifurcating the lower half of the heater tip 2' into two, thereby forming a two-legged iron body.

[0044] Specifically, the heater tip 2' has a soldering iron space 40 formed as a recess in the middle of the soldering iron portion 6' located at the bottom of the heater tip 2' in the thickness direction, extending in the left-right direction (from one connecting arm 7 to the other connecting arm 7), and this soldering iron space 40 is open downward. The soldering iron body 11 and the soldering iron tip 13 are provided on both the front and back sides of the heater tip 2', sandwiching the soldering iron space 40. In other words, the soldering iron portion 6' of the heater tip 2' has two soldering iron bodies 11 spaced apart from each other and two soldering iron tips 13 spaced apart from each other. Furthermore, each iron body 11 has a groove 20 formed on its outer surface and a groove 20' formed on its inner surface, and each has an iron recess 15 with a temperature measuring attachment portion 35 protruding therefrom, so that the temperature measuring junction (temperature measuring portion) 3a of the thermocouple 3 can be attached to each temperature measuring attachment portion 35, and the plate thickness of each iron tip portion 13 is set thinner than the plate thickness of the connecting arm portion 7.

[0045] By configuring the heater tip 2' with such a soldering iron portion 6', two locations can be simultaneously subjected to thermocompression bonding using the two soldering iron tips 13, thereby improving the efficiency of the thermocompression bonding work. Furthermore, by setting the dimension of the soldering iron space 40 in the thickness direction, the distance (pitch) between the two soldering iron tips 13 and the size of the soldering iron tip surface 13a of each soldering iron tip 13 can be adjusted according to the workpiece.

[0046] In the above-described embodiment, an oxidation-resistant coating layer may be formed on the surface of the heater tip to enhance oxidation resistance.

[0047] The oxidation-resistant coating layer will be described below. The heater tip is subject to repeated heating and cooling each time it is thermocompressed, so its surface is prone to oxidation, particularly in the vicinity of the soldering iron 6 (heat-generating portion) and in the portion where the thermocouple 3 is welded. This can lead to problems, such as peeling of the oxidized portion near the heat-generating portion, reducing its strength and causing breakage when pressure is applied, or corrosion of the welded portion of the thermocouple, reducing its strength and ultimately causing the thermocouple to come off and become unusable.

[0048] Therefore, in this embodiment, an oxidation-resistant coating layer is formed on the surface of the heater tip to improve oxidation resistance. The manufacturing process will be described in detail below. First, for the metal plate serving as the base material (base material), specifically, it is desirable to use a so-called superhard material (hardness HV 900-2400) (official name: superhard alloy, an alloy sintered from hard metal carbide powder), which has superior abrasion resistance compared to the conventionally commonly used tungsten (hardness HV 430) and tungsten alloy (hardness HV 200-400). This superhard material plate is then cut into the desired shape by wire cutting. Next, the cut piece is subjected to a plating pretreatment, and then immersed in a melting tank and current is applied to form a nickel oxidation-resistant coating layer on the surface of the cut piece, i.e., nickel plating. The cut piece is then removed from the melting tank and subjected to post-treatment such as cleaning. Then, as in the above-described embodiment, the temperature-measuring junction 3a of the thermocouple 3 is laser-welded to the temperature-measuring fastening portion 35. During this welding, a nickel layer is formed on the surface (the fastening contact surface 35a) of the temperature-measuring fastening portion 35, which enhances wettability and improves the reliability and strength of the weld. Furthermore, enhanced wettability during welding allows the laser output to be reduced compared to conventional methods, minimizing damage to the base material and improving quality and energy savings. After welding the thermocouple 3 is complete, a further plating pretreatment is performed: the heater chip unit 1 with the thermocouple 3 attached is immersed in an electrolyte, and nickel plating is applied to the entire surface, including the temperature-measuring contact 3a of the thermocouple 3.

[0049] The use of the heater tip unit 1 manufactured in this manner improves oxidation resistance, thereby suppressing peeling and strength loss due to oxidation of the soldering iron part 6 and the thermocouple 3 mounting portion, thereby improving durability. In particular, using a superhard material as the base material and applying nickel plating improves wettability and weldability, thereby reliably improving durability. Since the main component of thermocouples is nickel, nickel plating has good compatibility. Furthermore, the oxidation-resistant coating is not limited to nickel plating, and gold plating, for example, may also be used.

[0050] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The present invention is not limited to the above description, but is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0051] REFERENCE SIGNS LIST 1 heater tip unit 2, 2' heater tip 3 thermocouple 3a temperature measuring junction 3b conductor 6, 6' iron part 7 connecting arm 11 iron body 13 iron tip 13a iron tip surface 15 iron recess 17 mounting hole 20, 20' groove 21 thin-walled part 25 wire 26 wire coating material 27 outer coating material 30 conductor storage space 30a opening 31 retaining recess 32 wire retaining portion 35 temperature measuring fastening portion 35a fastening contact surface 36 recess 40 iron space

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