JPH06232219A - Tab tape, bonding tool, bonding device, and bonding method - Google Patents

Abstract

PURPOSE:To obtain a highly reliable semiconductor device having a high packaging density which needs a smaller number of steps by the use of a bonding tool having a stepped multilayer TAB tape and a stepped tool head. CONSTITUTION:When bonding is carried out using a multilayer TAB tape to obtain a semiconductor device having a high packaging density, a conventional method results in many steps or a connection failure at a connected portion of leads of the TAB tape. To obviate such problems, a bonding tool is provided with a tool head which has first and second stepped bonding surfaces 21 and 22. A temperature distribution in the first and second bonding surfaces 21 and 22 of the tool head is biassed using heaters 29 and 29' within the bonding tool.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TAB tape having a multi-layer wiring structure, a bonding tool used for bonding the TAB tape to a semiconductor element, and these TAB tapes. And a bonding method using a bonding tool. A conventional semiconductor element mounting structure is as follows.
For example, the multi-layer TAB disclosed in JP-A-64-19737
There are one using a tape, one using a wiring board having a multilayered conductive layer disclosed in Japanese Patent Publication No. 2-37097, and a TAB disclosed in Japanese Patent Laid-Open No. 4-48741.
There is a tape that is divided into many times and then laminated and adhered. FIG. 19 is a vertical sectional view of an example of a semiconductor element mounting structure disclosed in JP-A-64-19737. A plurality of layers of leads 3-a, 3-b, and 3-c are alternately laminated on the TAB tape 1 with the insulating films 2-a and 2-b sandwiched therebetween to form the semiconductor element 6.
Are formed in a stepwise manner so as to adhere to the respective electrodes 4-a, 4-b, 4-c. Then, the semiconductor element 6 is mounted on the inner lead portion of the multilayer film substrate (multilayer TAB tape) 5. Further, the connection between the outer lead portion and the wiring board in the case of the conventional example shown in FIG. 19 is not disclosed. The semiconductor device disclosed in Japanese Patent Publication No. 2-37097 has a basic structure similar to that shown in FIG. Specifically, a flip-chip IC that directly connects a semiconductor device and a wiring board without using a TAB tape is used, and the wiring board has a multi-layer structure. FIG. 20 is a vertical sectional view showing an example of a semiconductor element mounting structure disclosed in Japanese Patent Laid-Open No. 4-48741. Three rows of electrodes 8 are formed around the semiconductor element 7. The film substrates 9-a, 9-b, 9-c are independent of each other. The film substrate 9-a has leads 10-a connectable to the outermost peripheral electrodes 8-a of the semiconductor element 7, and the film substrate 9-b is a lead 10 connectable to the second electrode 8-b.
-B, the film substrate 9-c is the innermost electrode 8-c.
Has a lead 10-c connectable to. First, the lead 10-a of the film substrate 9-a is connected to the outermost electrode 8-a of the semiconductor element 7 by a normal thermocompression bonding method. Then, the lead 10-b of the film substrate 9-b is bonded to the second electrode 8-b, and finally the lead 10-c of the film substrate 9-c is bonded to the innermost electrode 8-c by thermocompression bonding. Connected by. First, in the case of the conventional example shown in FIG. 19, when a semiconductor element is mounted on a film substrate, a lead is generally connected to an electrode of the semiconductor element by a thermocompression bonding method. However, in the structure as shown in FIG. 17, the leads 3-a and 3-b other than the lead 3-c connected to the innermost electrode are formed.
The insulating films 2-a and 2-b exist between the bonding tool and the bonding tool for thermocompression bonding. Therefore, lead 3-
Since heat is blocked by the leads 3-b and 3-c and the insulating films 2-a and 2-b when thermocompression bonding of a is performed, the existing bonding tool requires advanced technology for thermocompression bonding. Was done. Although the heights of the metal bumps which are the electrodes 4-a, 4-b, 4-c are changed, it is difficult to change the height of the metal bumps delicately because the number of processes increases. Labor was needed. Further, the heat conduction to the electrodes 4-a and the electrodes 4-b is caused by the insulating films 2-a and 2-b and the leads 3-b and 3.
There is also a drawback that the reliability of thermocompression bonding is low because it is hindered by -c. Next, in the case of the conventional example shown in FIG. 20, since thermocompression bonding is performed many times, there is a drawback that the number of steps is increased and the cost is increased. The present invention has been made in view of such circumstances, and its object is to reduce the number of steps,
An object of the present invention is to provide a method for manufacturing a semiconductor device having high reliability and high packaging density. According to the present invention, one end is formed so as to project into a device hole as an inner lead portion connected to electrodes formed in a plurality of rows on the surface of a semiconductor element to be connected. , The plurality of conductive layers and each of these conductive layers are formed on the TAB tape body so that the other end forms outer lead portions connected to a plurality of wirings formed in a plurality of rows on the surface of the wiring substrate to be connected. In the TAB tape in which the insulating layers interposed between the tapes are alternately laminated, the laminated conductive layers are extended so as to be connected to the electrodes in the central portion of the semiconductor element as the conductive layers are separated from the tape body. Contact with the formed inner lead portion and with the wiring on the wiring board formed away from the center of the semiconductor element as the conductive layer moves away from the wiring board. The TAB tape is characterized by having each outer lead portion of the conductive layer corresponding to each inner lead portion of the conductive layer formed by being continuously stretched. In a bonding tool used for inner lead bonding of the TAB tape and the electrodes of the semiconductor element, the T
The bonding surface of the bonding tool, which is in contact with the inner lead portion of the AB tape, is the first bonding surface of the conductive layer formed on the semiconductor element side of the stacked conductive layers, which is the first bonding surface for bonding the inner lead. The bonding tool is formed so as to be separated from the TAB tape body from a second bonding surface for bonding the inner lead of the conductive layer formed near the semiconductor element. . Then, in a bonding tool used for outer lead bonding of the TAB tape and the wiring of the wiring board, the T
The bonding surface of the bonding tool that is in contact with the outer lead portion of the AB tape is a first bonding surface of the conductive layer formed closest to the wiring board of the stacked conductive layers, which is the first bonding surface for bonding the outer lead. The bonding tool is formed so as to be separated from the wiring board from a second bonding surface for bonding outer leads of a conductive layer formed closest to the wiring board. According to the above-mentioned means, the TAB having the multi-layer structure is formed.
The number of steps can be reduced in the semiconductor device manufacturing process using the tape, the multilayer TAB tape and the semiconductor element can be reliably connected, and the packaging density of the semiconductor device can be improved. ,reliable,
A semiconductor device having a high packaging density can be obtained. Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a perspective view of a first embodiment of the present invention, and FIG. 2 is a view showing positions of electrodes 11 of a semiconductor element 12 used in the present invention. This semiconductor element 12 is
The electrodes 11 are arranged in two rows around the semiconductor element 12. This is because the number of electrodes is increased and the mounting density is improved without increasing the outer shape of the semiconductor element 12 while keeping the lead pitch at a level where there is no short circuit with adjacent leads. Next, FIGS. 3A, 3B and 4 show a TAB tape used in the present invention. In FIG. 4, the insulating film 13 and the leads 14 and 15 are collectively attached to one side of the polyimide film 1. The inner lead portion 16 of the TAB tape and the lead 14 of the outer lead portion 17 of the TAB tape.
15 have different lengths, and the leads 15 on the semiconductor element side are shorter. The insulating film 13 shown in FIG. 4 has the same length as the lead 15 or slightly the device hole 18.
Although it extends toward the center of the lead 14, it does not reach the end point of the lead 14. FIGS. 1, 5 and 6 show a first embodiment of the tool head 19 of the bonding tool used in the present invention. The first bonding surface 21 of the tool head 19 used for connecting the leads 15 is the second bonding surface 2 of the tool head 19 used for connecting the leads 14.
2, the insulating film 13 and the lead 14 are formed to have a step approximately equal to the thickness of the lead 14. As shown in FIGS. 7 and 8, the connecting portion between the lead and the terminal is heated and pressed, Bonding is performed while forming the leads 14. Further, as shown in FIG. 8, the first bonding surface 21 and the second bonding surface 22 are divided into three parts and bonded to the tip of the tool head holder 23. That is, two slits 20 are provided at the boundary between the first bonding surface 21 and the second bonding surface 22 in the tool head holder 23 that holds the tool head 22. The slit 20 is provided to prevent the temperature difference between the heater 29 and the heater 29 'from interfering with each other and reducing the temperature difference between the first bonding surface 21 and the second bonding surface 22 as much as possible. The bonding tool shown in FIG. 8 solves the drawback that the conventional thermocompression bonding has low reliability. That is, the first bonding surface 21 used for connecting the outer peripheral portion has a higher temperature than the second bonding surface 22 used for connecting the convex portion of the bonding tool. With such a structure, even if the conduction of heat to the leads 15 is hindered by the insulating film 13 and the leads 14, reliable thermocompression bonding can be performed. When the temperature of the first bonding surface 21 is higher than that of the second bonding surface 22, such a structure can be realized. Specifically, as shown in FIG. 8, since the first bonding surface 21 and the second bonding surface 22 are individually heated, there are a heater 29 and a heater 29 'in the bonding tool. The difference in temperature between the parts is measured by 30, and the heater 29 '
It is realized by raising the set temperature of. When the bonding tool as shown in FIG. 8 is used, the temperature difference between the respective bonding surfaces of the bonding tool divided by the three thermocouples 30 is measured, and the set temperatures of the heaters 29 and 29 'are controlled to ensure reliability. It is possible to bond easily. Furthermore, since the set temperature can be freely changed by each of the bonding surfaces described above, the material, thickness, and other conditions of the insulating film 13 and the leads 14 change to change the degree of heat conduction, and the electrode 26. Even if the bonding material such as Au or Sn or the bonding temperature is changed, the electrode 26 as well as the electrode 27 can be stably bonded. When the bonding surface of the bonding tool has a uniform flat surface as in the conventional example, the surface area of the flat surface is large, so that it is difficult to increase the flatness during the manufacturing of the bonding tool, and the bonding process is difficult. It had been deformed by thermal expansion during use. Therefore, there are problems that stable bonding cannot be performed, defective bonding is partially caused, and pressure is not evenly applied. When the bonding surface is formed into a convex shape as proposed this time, the surface area of each plane of the first bonding surface 21 and the second bonding surface 22 is small, so that it is easy to increase the flatness and deformation due to thermal expansion. Is also easy to prevent. On the other hand, as a second embodiment, FIGS.
The connection of the outer lead portion 17 of the TAB tape in FIG. That is, after the outer lead portion 17 of the TAB tape and the wirings 32 and 33 of the wiring board 34 are aligned, they are connected using the bonding tool shown in FIG. In the bonding tool shown in FIG. 9, the outer lead portion 17 side of the TAB tape has a step approximately equal to the thickness of the insulating film 13 and the lead 14 with respect to the device hole 18 side of the TAB tape in FIGS. 3 and 4. And is formed with this bonding tool as shown in FIGS. 10 and 11.
Bonding is performed while heating and pressurizing a connecting portion between the wiring 15 and the wirings 32 and 33 of the wiring board 34 to form the leads 14. Here, as in the bonding tool shown in FIG. 8, a heater 31 and a heater 31 'are provided for heating the first bonding surface 21' and the second bonding surface 22 ', respectively. A slit 20 'is also provided to prevent the temperatures of the first bonding surface 21' and the second bonding surface 22 'from interfering with each other as much as possible. The present invention is not limited to the above embodiments, and can be variously modified without changing the gist of the invention. FIG. 12 shows a third embodiment. In this embodiment, there is only one heater 29 in the tool head holder 23, but the tool head having the second bonding surface 22 has a layer 3 of a metal (eg titanium) having a low thermal conductivity.
5 is inserted. This is because the tool head is usually composed of diamond, but the temperature of the second bonding surface 22 must be lower than that of the first bonding surface 21. The reason is that the first bonding surface 21 is used for bonding the electrode 26 and the lead 15, and heat must be transmitted through the insulating film 13 and the lead 15, and the temperature of the heater 29 must be set high. There is an electrode 27
This is because if the bonding portion of the lead 14 is kept at a high temperature, it may be unsuitable for the bonding temperature condition, or the semiconductor element may be damaged by the high heat from the first bonding surface 21. Therefore, by inserting a metal having a low thermal conductivity such as titanium into the bonding head, the second bonding surface 22 is prevented from having an excessively high temperature. As a fourth embodiment, FIG. 3 and FIG.
For the connection of the outer lead portion 17 of the TAB tape in, the bonding tool shown in FIG. 13 is used. This bonding tool is also provided with a first bonding surface 21 'and a second bonding surface 22' similar to those of the second embodiment. Then, the tool head having the second bonding surface 22 'is provided with the titanium layer 35' as in the third embodiment, and the second bonding surface 22 'is better than the first bonding surface 21'. The temperature is getting lower. 14 and 1 using this bonding tool
As shown in FIG. 5, the connecting portions of the leads 14 and 15 and the wirings 32 and 33 of the wiring board 34 are heated and pressed to form the leads 14 while performing bonding. Further, FIG. 16 shows a fifth embodiment. In this embodiment as well, there is only one heater 29 in the tool head holder 23, but a support plate (hereinafter referred to as the forming plate 2) that supports the TAB tape during pressure bonding by the bonding tool.
8) and a heater 36 is provided on the support of the forming plate 28. By heating the forming plate 28 by the heater 36, the leads 15 are indirectly heated. Therefore, the set temperature of the heater 29 may be set to a temperature suitable for the thermocompression bonding of the electrode 27 and the lead 14 by the second bonding surface 22, and the insulating film 13 and the lead 15 ensure the electrode 26 and the lead 15. First bonding surface 2 that can be bonded
Even if the heat conduction to 1 is disturbed, the temperature of the bonding portion of the lead 15 to the electrode 26 is increased by the heater 36 and the forming plate 28, and the electrode 26 and the lead 15 can be reliably bonded. As is common to each of the above embodiments,
Forming plate 2 is used when there are two or more bonding tools to support various types of semiconductor devices of different sizes.
It is advisable to prepare two or more sheets 5 so that they can be exchanged together when the bonding tool is exchanged. The outer lead portions 17 shown in FIGS. 3 and 4 are connected to each other by sandwiching the insulating film 13 on the TAB tape 1 without using a bonding tool as in the sixth embodiment shown in FIG. Multiple layers of leads 14
The length of the outer lead portion 17 of 15 does not change depending on the layer, and after forming the outer lead, the wiring board 34 is formed.
It may be connected through a reflow furnace after positioning so as to be connected to the upper wirings 32 and 33. Further, as shown in the seventh embodiment of FIG. 18, the thickness of the solder material 37 on the wirings 32 and 33 on the wiring board 34 is changed to use a conventional bonding tool having a flat tool head. It is also conceivable that they are connected together. In all of the above-mentioned embodiments, the TAB tape, the semiconductor element and the wiring board are connected by thermocompression bonding as in the conventional bonding tool having a flat tool head. Furthermore, in all of the above-mentioned embodiments, the metal projections are provided on the electrodes on the semiconductor element, but the same effect can be obtained by previously providing the metal projections on the leads of the TAB tape. Although the TAB tape having a three-layer structure is taken as an example in the above embodiment, the TAB tape is not limited to three layers and may have any number of layers as long as it has a multilayer structure. A bonding tool corresponding to it can be used. As described above, since the bonding tool and the bonding apparatus of the present invention used for adhering a multi-layered TAB tape and a semiconductor element have the above-mentioned structure, the multi-layered TAB tape is formed. There is an effect that the number of steps of adhering the semiconductor element is reduced, the reliability of the adhering is increased, and a semiconductor device having a high packaging density can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a bonding tool used for inner lead bonding of the present invention. FIG. 2 is a plan view of a semiconductor device used in the present invention. FIG. 3A is a plan view of the multilayer TAB tape used in the present invention as seen from the semiconductor element side. (B) is the top view which looked at the multilayer TAB tape used for this invention from the bonding tool side. FIG. 4 is A- of the multilayer TAB tape of FIGS. 3 (a) and 3 (b).
Sectional drawing in line A '. FIG. 5 is a side view of a tool head of a bonding tool used for inner lead bonding of the present invention. FIG. 6 is a plan view of a tool head of a bonding tool used for inner lead bonding according to the present invention as viewed in the direction of arrow Y in FIG. FIG. 7 is a perspective view showing a state in which inner lead bonding is performed using the bonding tool of the present invention. FIG. 8 is a cross-sectional view taken along the line BB ′ of FIG. 7 showing a state where inner lead bonding of the first embodiment is performed using the bonding tool of the present invention. FIG. 9 is a perspective view of a bonding tool used for outer lead bonding according to a second embodiment of the present invention. FIG. 10 is a perspective view showing a state in which outer lead bonding of the second embodiment is being performed using the bonding tool of the present invention. FIG. 11 is a cross-sectional view taken along the line C-C ′ of FIG. 10 showing the outer lead bonding of the second embodiment using the bonding tool of the present invention. FIG. 12 is a cross-sectional view taken along the line BB ′ of FIG. 7 showing a state in which inner lead bonding of the third embodiment is performed using the bonding tool of the present invention. FIG. 13 is a perspective view of a bonding tool used for outer lead bonding according to a fourth embodiment of the present invention. FIG. 14 is a perspective view showing a state in which outer lead bonding according to the fourth embodiment is performed using the bonding tool of the present invention. FIG. 15 is a cross-sectional view taken along the line D-D ′ of FIG. 14 showing the outer lead bonding of the fourth embodiment using the bonding tool of the present invention. FIG. 16 is a sectional view taken along the line BB ′ of FIG. 7 showing a state in which inner lead bonding of the fifth embodiment is performed using the bonding tool of the present invention. FIG. 17 is a vertical cross-sectional view showing a state in which outer lead bonding of the sixth embodiment is performed using the TAB tape of the present invention. FIG. 18 is a vertical cross-sectional view showing a state in which outer lead bonding of the seventh embodiment is performed using the TAB tape of the present invention. FIG. 19 is a vertical cross-sectional view of an example of a semiconductor element mounting structure disclosed in Japanese Patent Application Laid-Open No. 64-19737. FIG. 20 is a vertical sectional view of an example of a semiconductor element mounting structure disclosed in Japanese Patent Laid-Open No. 4-48741. [Explanation of Codes] 1 ... Polyimide film (TAB tape body) 2-a, 2-b, 9-a, 9-b, 9-c, 13 ... Insulating film 3-a, 3-b, 3-c・ 10-a ・ 10-b ・ 10-
c ・ 14 ・ 15 ... Lead 4-a ・ 4-b ・ 4-c ・ 8-a ・ 8-b ・ 8-c ・ 1
1, 26, 27 ... Electrode 5 ... Multi-layer TAB tape 6, 7, 12, 25 ... Semiconductor element 16 ... Inner lead part 17 ... Outer lead part 18 ... Device hole 19 ... Tool head 20 ... Slit 21, 21 '... First Bonding surface 22/22 '... Second bonding surface 23 ... Bonding head holder 24 ... Mounting shank 28 ... Forming plate 29.29'.31.31'.36 ... Heater 30 ... Thermocouple 34 ... Wiring board 32.32 33 ', 33', 33 '... Wiring 35, 35' ... Titanium layer 37 ... Solder material

Claims (1)

Claim: What is claimed is: 1. One end is formed so as to project into the device hole as an inner lead portion connected to electrodes formed in a plurality of rows on the surface of the semiconductor element to be connected, and the other end is connected. To form outer lead portions connected to a plurality of wirings formed in a plurality of rows on the surface of the target wiring board, T
In a TAB tape in which a plurality of conductive layers and insulating layers interposed between the conductive layers are alternately laminated on an AB tape body, the semiconductor element of the semiconductor element is separated as the laminated conductive layers are separated from the tape body. The inner lead portion formed to extend so as to be connected to the electrode at the center, and the wiring formed to be separated from the center of the semiconductor element as the conductive layer is separated from the wiring substrate. A TAB tape, comprising: each outer lead portion of the conductive layer corresponding to each inner lead portion of the conductive layer formed so as to be connected to the wiring on the substrate. 2. One surface of the wiring board to be connected has one end projecting into the device hole as an inner lead portion connected to electrodes formed in a plurality of rows on the surface of the semiconductor element to be connected. T is formed so as to form outer lead portions connected to a plurality of wirings formed in a plurality of rows above.
In a TAB tape in which a plurality of conductive layers and insulating layers interposed between the conductive layers are alternately laminated on an AB tape body, the semiconductor element of the semiconductor element is separated as the laminated conductive layers are separated from the tape body. The inner lead portion is formed so as to extend so as to be connected to the electrode in the center portion, and corresponds to each inner lead portion of the conductive layer formed as the conductive layer is separated from the wiring board. A TAB tape, wherein the end faces of the outer lead portions of the conductive layer are substantially flush with each other. 3. A bonding tool used for inner lead bonding between a TAB tape having a three-layer structure and an electrode of the semiconductor element among the TAB tapes according to claim 1 or 2, wherein the TAB tape is bonded at the time of bonding. The bonding surface of the bonding tool that abuts the inner lead portion is the first bonding surface for bonding the inner lead of the conductive layer formed on the semiconductor element side of the stacked conductive layers, which is the most semiconductor element. A bonding tool, which is formed so as to be separated from the TAB tape body from a second bonding surface for bonding the inner lead of the conductive layer formed so as to be separated from. 4. A bonding tool used for inner lead bonding of the TAB tape according to claim 1 and an electrode of the semiconductor element, wherein the bonding tool comes into contact with the inner lead portion of the TAB tape during bonding. The bonding surface of
The inner lead of the conductive layer formed so that the first bonding surface of the conductive layer formed on the semiconductor element side of the stacked conductive layers for bonding the inner lead is most distant from the TAB tape body. Is formed so as to be spaced apart from the semiconductor element from a second bonding surface for bonding, and a bonding surface formed between the first and second bonding surfaces is the first bonding surface from the second bonding surface. The bonding tool, which is sequentially formed in a step-like manner so as to be separated from the semiconductor element in the bonding surface direction. 5. A bonding apparatus used for inner lead bonding between the TAB tape according to claim 1 and the electrode of the semiconductor element, according to claim 3.
A bonding apparatus comprising the bonding tool according to claim 4. 6. The bonding apparatus according to claim 5, wherein
A support plate for supporting the TAB tape having an opening through which the semiconductor element is inserted at a position facing the bonding tool via the TAB tape, and heating for heating the TAB tape supported by the support plate. A bonding apparatus having a device. 7. A bonding tool for use in outer lead bonding of the TAB tape of claim 1 having a three-layer structure and the wiring of the wiring board, wherein the outer lead portion of the TAB tape is bonded at the time of bonding. The contacting bonding surface of the bonding tool is such that the first bonding surface for bonding the outer lead of the conductive layer formed closest to the wiring board among the stacked conductive layers is the farthest from the wiring board. A bonding tool formed so as to be separated from the wiring board from a second bonding surface of the conductive layer formed by bonding the outer leads. 8. The TAB of claim 1.
In a bonding tool used for outer lead bonding the tape and the wiring of the wiring board, the bonding surface of the bonding tool that comes into contact with the outer lead portion of the TAB tape during bonding is the most conductive layer among the stacked conductive layers. The first bonding surface for bonding the outer lead of the conductive layer formed on the wiring board side is the wiring from the second bonding surface for bonding the outer lead of the conductive layer formed farthest from the wiring board. A bonding surface formed so as to be spaced apart from the substrate and formed between the first and second bonding surfaces extends from the second bonding surface in the direction of the first bonding surface.
A bonding tool, which is sequentially formed in a step-like shape so as to be separated from the AB tape body. 9. A bonding apparatus used for outer lead bonding between the TAB tape according to claim 1 and the wiring of the wiring board, comprising the bonding tool according to claim 7 or 8. . 10. The bonding tool according to claim 3, 4 or 7, or 8, wherein each bonding surface formed on the bonding tool is heated by a heating device that individually heats each bonding surface. Bonding tool characterized by 11. The bonding tool according to claim 10, wherein the heating device for heating each bonding surface is capable of temperature control for each heating device. 12. A bonding method, wherein the TAB tape according to claim 1 or 2 and the electrode of the semiconductor device are bonded by using the bonding device according to claim 5. 13. A bonding method, wherein the TAB tape according to claim 1 or 2 and the electrode of the semiconductor device are bonded by using the bonding device according to claim 6. 14. A bonding method, wherein the TAB tape of claim 1 and the wiring of the wiring board are bonded by using the bonding apparatus of claim 9. 15. The bonding of the TAB tape according to claim 2 and the wiring of the wiring board, after forming the outer lead of the TAB tape so that the wiring of the wiring board and the end surface of the outer lead are connected to each other. A bonding method, characterized in that the wiring of the wiring board and the end faces of the outer leads are bonded through a reflow furnace in a state of being in contact with each other via a bonding member.