TW564538B - Wire bonding method, method of forming bump and bump - Google Patents

Abstract

A wire bonding method, a method of forming bump and a bump are provided to prevent contacts between a wire and a circuit board and between the wire and wirings on the circuit board after the wire and a bump are bonded together, and to prevent the occurrence of wire bending while bonding the wire and the bump. While bonding a wire 50 between a first conductor 10 and a second conductor 20, a bump 51a is priorly formed on the second conductor 20 in a way of ball bonding, a capillary 40 is then driven to move along a predetermined path so as to form an inclined surface 51c at the top of the bump 51a. The wire 50 is looped from the first conductor 10 toward the bump 51a after a first bonding is performed on the first conductor 10, then a second bonding is performed on the inclined surface 51c.

Description

564538 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a wire bonding method for connecting a wire between two conductors, and a bump forming method and a bump at that time. In particular, when the first conductor is bonded once and the second conductor is bonded twice to connect the wire between the first conductor and the second conductor, in order to prevent the wire-bonded wire from contacting Other wire bonding methods, such as wire bonding or surface contact with a circuit substrate, which are performed by forming a bump of a suitable shape on the second conductor in advance by ball bonding, and a method of forming the bump of a suitable shape, and Bump. [Prior art] When wire bonding is used, a capillary with a gold (Au) wire inserted in the capillary is used to form a ball at the front end of the eight-wire line protruding from the capillary with a discharge from the gas torch electrode, and the capillary is positioned on the semiconductor After the bonding is performed once on the wafer, the capillary is moved to the wiring and coupled twice, so that the AU line is connected between the semiconductor wafer and the wiring, which is a commonly used method. In this situation, the wiring material is, for example, copper (Cu), nickel (Ni), flash gold plating and other materials with poor adhesion to the Au wire ^, cannot be directly bonded on the wiring, so The jointed part is first formed with a silver-plated or copper-thick film. However, it is not practically ideal to provide such a substrate. Therefore, a method of directly bonding the wiring to the wiring even if the wiring material is a material having poor adhesion to the Au wire is desired. ] This will be described, for example, in Japanese Unexamined Patent Publication No. 10_ 1 1 247 1 which describes that as shown in FIG. 10, ball bonding is performed on the second conductor 20 of the circuit board 30 to open 3

Page 9 313975.ptd 564538 V. Description of the invention (2) The bump 5 1 a is formed, and then wedge bonding is performed on the opposite side of the bump 5 1 a from the first conductor 1 〇, and then 1 conductor 10 is bonded once ', then the wire 50 is wound from the side of the first conductor 10 to the bump $ 1a, and then bonded twice on the bump 51a to connect the wire to the i-th conductor 1〇 And the second conductor 20. According to this method, after the bump is formed by ball welding, a wedge joint is performed on the second conductor behind the bump (position opposite to the first conductor position of the bump), so the wedge joint becomes a curved shape. No bump trailing. In other words, it is recorded that when the two joints are performed on the bumps, as shown in FIG. 丨, the capillary 40 is positioned in the curved portion 5U of the line 50 extending from the bump 51 into the second through-hole 41. At the position, the side-curved portion 51b of the through-hole 41 is used to join the two with the wire 50 pressed against the inner wall of the other side of the through-hole 41. [Summary of the invention] The method of f in the above block is shown in Fig. 11 as 'Fig. 11' is convex, i-shaped joints are connected with the line, that is, the adjacent line A between the curved surfaces A = When the combined position is shifted, there will be the result of line bending, and there is a concern of contact between the phase M lines. In addition, although the wedge joint after the bumps are formed is formed to be bent backward to ensure sufficient inclination to suppress the occurrence of line tails, but the connection between the wire and the bumps cannot be prevented accurately. As indicated by the dotted line in FIG. 11, the contact between the line 50 and the circuit board 30 ^ line 50 and the wiring generated after the block 51a and the line 50 cannot be sufficiently contacted.

313975.Ptd Page 10 564538 V. Description of the invention (3) The object of the present invention is to provide a wire bonding method, a bump formation method and a bump, which can prevent the occurrence of a wire and a circuit substrate after the bump and the wire are bonded. Contact, and contact between the wire and the wiring, and can prevent the bending of the wire when the bump and the wire are bonded. In order to solve the above problems, the present invention adopts the following method. The wire bonding method of the present invention is a method for connecting a wire between a first conductor and a second conductor, and includes the steps of forming a bump on the second conductor by ball bonding; and forming a slope on the upper portion of the bump. Surface step; a step of bonding once to connect one end of the wire to the first conductor; and a step of winding the wire from the first conductor to a bump on the second conductor and then performing a second joint to wire the other A step of connecting one end to an inclined surface on the upper portion of the bump. The wire bonding method of the present invention is a method of using a through-hole to penetrate a wired capillary tube and connecting a wire between a first conductor and a second conductor. The method includes: performing a ball by placing a capillary tube on the second conductor. Soldering to form a bump on the second conductor; after the capillary is moved upward, the capillary is moved laterally to a position opposite to the first conductor, and the capillary is lowered to cut the wire to A step of forming an inclined surface on the upper portion of the bump; a step of performing a bonding to connect one end of the wire to the first conductor; and a second bonding so that the capillary is located on the inclined surface of the upper portion of the bump, and The bottom of the capillary is used to connect a line extending from the capillary to the inclined surface of the upper portion of the bump, and the step of cutting the line near the joint is in a preferred embodiment of the wire bonding method of the present invention. , The inclined surface of the upper part of the bump is formed as a flat surface or a concave surface, and the two joining steps include making the

313975.ptd Page 11 564538 V. Description of the invention (4) The capillary is located on the inclined surface of the upper part of the bump, and the bottom of the capillary is used to crimp the wire to the inclined surface of the upper part of the bump. Further, in a preferred embodiment of the wire bonding method of the present invention, the inclined surface of the upper portion of the bump is such that an inclined angle formed by a straight line connecting both ends of the inclined surface with respect to the second conductor surface is directed toward the second conductor surface. The first conductor is formed with an opening angle of 2 ° to 60 °. Furthermore, in the method for forming a bump of the present invention, when the first conductor is bonded once and the second conductor is bonded twice to connect the wire between the first conductor and the second conductor, A method of forming bumps on the second conductor by ball bonding in advance includes the steps of lowering a capillary tube onto the second conductor and connecting a ball formed at the front end of the wire to the second conductor to form a bump; thereafter, A step of vertically raising the capillary; thereafter, a step of laterally moving the capillary in a direction opposite to a direction where the first conductor is located; and thereafter, lowering the capillary to press the bottom of the capillary to the protrusion And a step of laterally moving the capillary tube in the direction of the first conductor, and an inclined surface is provided on an upper portion of the bump. In addition, in the method for forming a bump of the present invention, the first conductor is bonded once and the second conductor is bonded twice to connect the wire between the first conductor and the second conductor in advance. A method of forming a bump on the second conductor by ball bonding includes the steps of lowering a capillary tube onto the second conductor and connecting a ball formed at the front end of the wire to the second conductor to form a bump; A step of vertically rising the capillary; a step of laterally moving the capillary in a direction toward the position of the first conductor; a step of vertically rising the capillary; and a step of moving the capillary toward the first guide

Page 12 313975.ptd ^ &045; 4538, description of the invention (5) The step of moving the capillary in the direction of the position where the capillary is moved to make the hairs thin * toward the branch; thereafter, and thereafter, the hair ;: Tube facing: Jf :: crimping the step of the bump; moving step, and in the direction of the position of the inspection " brother " position of the body transversely ^ square ^ upper part of the bump of the present invention is provided with an inclined surface. The inclined surface of the part is formed in a preferred embodiment, in which straight lines at both ends of the inclined continuous inclined surface formed by the second conductor surface on the bump are formed with respect to the opening angle. The angle becomes 2 toward the first conductor. To 60. It is performed on the second conductor on the second conductor: When the soil system is bonded once on the first conductor, and the body is connected in advance, the f conductor is connected to the first conductor and the second conductor and has a flat or concave surface. The inclination angle formed by the straight line connecting the upper surface of the stomach and the upper surface of the stomach with respect to the second conductor surface becomes 2 of the first conductor toward t. To 60. Form the angle. [Embodiment Mode] The following is a detailed description of the present invention based on the embodiments of the drawings. The same reference numerals in the drawings indicate equal parts. FIG. 1 shows a state where a wire is connected between a semiconductor wafer and a wiring by a wire bonding method according to an embodiment of the present invention. A semiconductor wafer 8 is mounted on a circuit board 30 made of a substrate such as a ceramic substrate, a printed circuit board, or a lead frame, etc., through a die mounting paste 6. A bonding pad (first conductor) 10 is formed on the semiconductor wafer 8. In addition, Ni, Cu, etc., which have poor adhesion to the Au wire 50, are formed on the circuit substrate 30.

313975.ptd Page 13 564538 V. Description of the invention (6) The wiring material 2 as the second conductor. Next, a method for wire bonding a bear according to an embodiment of the present invention will be described with reference to Figs. 2A to 2G. First, as shown in FIG. 2A, the state where the wire 50 is inserted through the through hole 41 of the capillary 40 is formed by an electric torch 60, and a ball 5 is formed at the front end of the wire 50 protruding from the capillary 40. As shown in FIG. 2B, the capillary 40 is lowered onto the wiring 20, and ball bonding (ba 1 1 bonding) is performed on the wiring 20 to form a ball 51 at the front end of the wire 50. The bumps 51a are formed by the ball welding. As shown in Fig. 2C, the capillary "from the center of the bump 5 1a" is opposite to the position where the bonding pad 10, which is the first conductor, is positioned. Move laterally. Thereafter, as shown in FIG. 2D, the capillary 40 is pressed downward again to crimp the bottom 4 2 of the capillary 40 to the surface of the bump 5 1 a to form an inclined surface 5 1 c on the upper portion of the bump 5 1 a. And cut the line 50. The bump 5 1 a formed as described above is shown in FIG. 3, and the inclination angle 0 of the inclined surface 5 1 c at the upper portion of the bump 5 1 a with respect to the plane of the wiring 20 that is the second conductor is 0 The opening angle of 2 ° to 60 ° is used as a guide for the line 50 when the line from the bonding pad 1 〇 is connected to the inclined surface 5 1 c on the upper part of the bump 5 1 a. Thus, the line 5 〇 is found after the experiment. That is, no U-shaped sagging is formed. Thereafter, as shown in FIG. 2E, the electric torch 60 is used to form a ball 5 2 at the front end of the line 50. Then, as shown in FIG. 2F, the capillary 40 is positioned on the bonding pad 10 of the semiconductor wafer 8 and bonded once. Next, as shown in FIG. 2G, the wire 50 from the bonding pad 10 is wound, and then the wire 50 is located on the upper part of the inclined surface 5 1 c of the upper part of the bump 5 1 a.

313975.ptd Page 14 564538 V. Description of the invention (7) The bottom 42 of the capillary 40 connects the wire 50 with the inclined surface 51c on the upper portion of the bump 51a and cuts the wire 50. Fig. 3 is an enlarged view when the line 50 and the inclined surface 5 1 c at the upper portion of the bump 5 1 a are joined in the step of the second G diagram. As described above, the inclination angle 0 of the upper surface 5 1 c of the bump 5 a is set to 2. To 6 0. Based on the positional relationship in the height direction of the first conductor (bonding pad) 10 and the second conductor (wiring) 20, it is experimentally known that this range is appropriate. That is, when a line is connected between the first conductor 丨 0 and the second conductor 20, when the position of the first conductor 丨 0 on the circuit substrate 30 is lower than that of the second conductor 20, the inclination angle 0 is set as If it is smaller, it is easier to guide the wound wire 50 from the first conductor i 0 to the upper surface of the bump 51 a on the surface of the second conductor 20. On the other hand, in the case where the position of the first conductor 10 is higher than that of the second conductor 20 ', conversely, the inclination angle Θ is made large to facilitate the guidance. Also, the above-mentioned joining of the wires is performed by using an ultrasonic wave applying device. Next, embodiments of the bump and complex forming method of the present invention will be described with reference to FIGS. 4 to 9. … Figure 4 shows the second and second conductors 20 on a circuit board 30 composed of a ceramic substrate, a printed circuit board, or a lead frame, etc., and a part of a tube forming a bonding device. 40 and the line which descends through its through hole 41 and has a ball formed at the tip 0. Next, an embodiment of the method of the present invention will be described with reference to Figs. 5A to 5F. &Amp; · First, at the end of the wire protruding from the through hole 41 at the bottom of the capillary 40, the ball 5 丨 is formed by the heat of an electric torch (not shown). Before 0, ^ 糸 is ~

564538 V. Description of the invention (8) General manufacturing steps. Next, in the first step, as shown in FIG. 5A, the capillary 40 is lowered onto the second conductor 20, and the ball 51 formed at the front end of the line 50 is joined to the second conductor 20 to form a bump 5a. Next, in the second step, as shown in Fig. 5B, the capillary 40 is raised vertically. Next, in the third step, as shown in Fig. 5C, the capillary tube 40 is moved laterally in a direction opposite to the direction where the first conductor 10 is located. In the fourth step, as shown in FIG. 5D, the capillary 40 is lowered, and the bottom 4 2 of the capillary 40 is crimped to the surface of the bump 5 1 a. Next, the fifth step is to move the capillary 40 laterally in the direction of the first conductor 10 as shown in FIG. 5E. The above steps are represented by the movement of the capillary tube. As shown in Fig. 2F, M1—MM3—M4—M5 is shown. As a result of these steps, the upper surface 5 1 c can be turned into a bump 5 1 a on the inclined surface. It is formed on the surface of the second conductor 20. In the above steps, the control of the moving distance and direction of the capillary 40 is performed in the following manner. Even if the bump 5 1 a formed by such control is shown in FIG. 6, it is connected to the first conductor 1. 0 and the second conductor 20 in a vertical cross-sectional view, the straight line connecting the two ends P 丨 and P of the upper surface 5 1 c of the bump 5 1 a with respect to the surface of the second conductor 20 at an inclination angle 0 is formed The opening angle is 2 ° to 60 ° toward the first conductor. Also in the figure, the symbol A represents the diameter of the base portion of the bump 5 1 a, the symbol B represents the thickness of the base portion, and the symbol C represents the height of the bump 5 1 a. In fact, the dimensions A, B, and C are related to the diameter of the line 50, the line

313975.ptd Page 16 564538 V. Description of the invention (9) When the diameter of 50 is 7 to 100 / m, the diameter A of the base can be in the range of 25 to 3 0 0 / m. The thickness B may be in a range of 4 to 6 // // m, and the height C of the bump may be formed in a range of 10 to 2 0 // in. For example, when a gold wire with a wire diameter of 3 0 0 // m is formed, a bump having a base diameter of A = 75 // m, a base thickness of B = 1 7 // m, and a bump height of 060 // m is formed. 51a. In another example, when a gold wire having a wire diameter of 50 // m, a bump 51a having a base diameter A = 190 / z m, a base thickness B = 35 / z m, and a bump height 0110 // m is formed. Next, another embodiment of the method for forming bumps according to the present invention will be described with reference to Figs. 7A to 7H. y First 'A ball 5 丨 is formed at the tip of a line 50 that protrudes from a through hole 41 at the bottom of the capillary tube 40 by the heat of an electric torch (not shown). 'Next, as shown in FIG. 7A, the first step is to lower the capillary 40 to the second conductor 20, and to join the ball 5 1 formed at the front end of the line 50 to the second conductor to form a bump 5 1 a. . 'Next, the second step is to raise the capillary 40 vertically as shown in FIG. 7B. The official 40 is directed toward the first conductor 10 to make the capillary 40 vertical. The third step is to make the capillary as shown in FIG. 7C. The direction of the position moves laterally. Next, the fourth process is ascended as shown in FIG. 7D. Next, the fifth step is shown in FIG. 7E, and the purine car ^, ^ edge capillary 40 is laterally moved in the opposite direction of the direction where the first conductor 10 is located. Furthermore, the sixth step is as As shown in Figure 7F, it is $, move. The capillary 40 is lowered and the bottom 42 of the capillary 40 is crimped to the surface of the bump 5 1 a.

564538 5. Description of the invention (ίο) Finally, as shown in FIG. 7G, the seventh step is to move the capillary 40 laterally in the direction of the first conductor 10. The above steps are represented by the movement of the capillary, as shown in Fig. 7H as M 1-M 2-M 3-^ M 4-M 5-M 6-M 7 and as a result of these steps, the above 5 The bump 5 1 a that 1 c becomes an inclined surface is formed on the surface of the second conductor 20. The control of the movement distance and direction of the capillary 40 in each of the above steps is performed in the following manner, and even if a bump is formed by such control, the first conductor is connected as shown in Figs. 8A and 8B. 10 and the cross section of the second conductor 20 in a vertical plane, the connecting blocks 5 1 a and the upper end 5 1 c of the two ends P r P 妁 are formed at an inclination angle 6 »of the straight line with respect to the surface of the second conductor 20 The opening angle is 2 ° to 60 ° toward the first conductor. In the above steps, when the capillary 40 is moved along the dotted line as shown in FIG. 7 (b), the amount of the curved portion 5 1 b stored on the line 5 0 of the bump 5 1 a will change, so The height of the finally formed bump 5 1 a can be made as shown in FIG. 8A, or the area of the upper part of the bump 5 1 a can be made wider than that of the base part as shown in FIG. 8B. Regarding the bump 5 1 a according to the embodiment of the present invention, as shown in FIG. 3, FIG. 6, FIG. 8A, and FIG. 8B, the upper surface 51 c is formed as a flat surface or a concave surface, and the first conductor 10 and the second conductor are connected at the same time. The cross-sectional view of the vertical surface of the conductor 20 is such that the inclination angle 0 of the two ends P ρ P of the connecting bump 5 1 a and the upper surface 5 1 c with respect to the plane of the second conductor 20 is formed toward the first conductor 1. Opening angle from 2 ° to 60 °. The bump 5 1 a having the shape described above is formed in advance on the surface of the second conductor 20.

31? 975.ptd Page 18 564538

V. Description of the invention (11) As shown in Figure 9, when the connecting wire 50 is wound from the first conductor 10 to the second conductor 20, the inclined surface becomes the guide surface ^, which can reduce the bending of the wire 50. , To reduce the contact between the wires or contact with the circuit board surface due to the looseness of the wires. [Effects of the Invention] As described above, according to the wire bonding method of the present invention, the inclined surface formed on the upper portion of the bump becomes a guide surface when the connection wire is wound from the first conductor to the second conductor, and the wire and the semiconductor can be prevented. The contact of the wafer or wire with the bonding pad. In addition, the upper surface of the bump is an inclined surface, so that the wire bending which occurs when the wire and the wire are bonded as previously is eliminated, and as a result, the adjacent wires after the wire bonding are not brought into contact. Furthermore, the wedge-shaped bonding system at the upper portion of the bump is formed as an inclined surface, and there is no remaining wire after the wedge-shaped bonding, and a thin semiconductor package can be made. In addition, when the inclined surface is made flat or concave, the joint area can be enlarged, and the joint strength can be increased, and the bump forming method according to the present invention can be increased. The cross section of the vertical plane of the 2 conductor is a bump with a straight line connecting the two ends of the first guide with respect to the second conductor plane. The inclination of the straight line to the 12 ° to 60 ° opening angle is a loop. There is less connection, minus 5. When the conductor, the 'inclined surface will become the guide surface and can make the curved contact of the wires S contact between the wires or the circuit board surface due to the looseness of the wires. At the same time, it can also prevent the wires from bending when the bumps are joined to the wires, and the bevels on the bumps can be reduced, so that when the inclination angle is small, a thin package can be reduced. In addition, the first conductor can freely form an inclined remaining line, and can

Page 19

564538 V. Description of the invention (12) At a high position, the connection of the wires can be easily and completely performed by making the tilt angle larger. In addition, since the area on the upper surface of the bump can be increased, the area to be joined with the wire can be enlarged, and the joint strength can be improved.

313975.pid Page 20 564538 Brief description of drawings [Simplified description of drawings] Fig. 1 is a cross-sectional view showing a state where a wire is connected between a semiconductor wafer and a wiring using a wire bonding method according to an embodiment of the present invention. Figures 2A to 2G are diagrams for explaining the bonding steps of an embodiment of the wire bonding method of the present invention. Fig. 3 is an enlarged cross-sectional view when the wire is connected to the inclined surface at the upper portion of the bump by performing two bondings. Fig. 4 is a diagram showing a state before the method for forming a bump according to the present invention, and showing a positional relationship between a first conductor, a second conductor, and a capillary on a circuit board. Figs. 5A to 5E are diagrams showing the formation steps of one embodiment of the bump forming method of the present invention, and Fig. 5F is a diagram showing the movement path of the capillary. Fig. 6 is a sectional view of a bump formed according to the embodiment shown in Figs. 5A to 5F. 7A to 7G are diagrams showing formation steps of other embodiments of the method for forming bumps according to the present invention, and FIG. 7H is a diagram showing the path of the movement of the capillary. 8A and 8B are cross-sectional views of bumps formed according to the embodiments shown in FIGS. 7A to 7H. Fig. 9 is a cross-sectional view showing an example of wire bonding using bumps formed according to an embodiment of the method for forming bumps according to the present invention. FIG. 10 is a diagram when wire bonding is performed using bumps formed by the previous bump formation method.

313975.ptd page 2] page 564538 page 1 1 is a diagram for explaining the problem of wire bonding using the bumps simply described by the previous bump formation method. 6 Wafer mounting 8 Semiconductor wafer 10 First conductor (bonding pad) 20 Second conductor (wiring) 30 Circuit board 40 Capillary tube 41 Through-hole 42 Bottom 50 Line 5 52 Ball 51a Bump 51b Bend 51c Inclined surface (upper surface) 60 Electric torch A The diameter of the bump base B The thickness of the base of the bump C The height of the bump Pr P2 End θ tilt angle

313975.ptd Page 22

Claims (1)

564538 6. Scope of patent application 1. A wire bonding method, which is a method of connecting a wire between a first conductor and a second conductor, including: a step of forming a bump on the second conductor by ball bonding; A step of forming an inclined surface on the upper portion of the bump; a step of bonding once to connect one end of the wire to the first conductor; and a step of winding the wire from the first conductor to the bump on the second conductor and then performing twice The step of joining to connect the other end of the wire to the inclined surface on the upper part of the bump. 2. The wire bonding method according to item 1 of the scope of the patent application, wherein the inclined surface of the upper portion of the bump is an inclined angle formed by a straight line connecting both ends of the inclined surface with respect to the second conductor surface toward the second conductor surface. The first conductor is formed with an opening angle of 2 ° to 60 °. 3. —A wire bonding method is a method of using a through-hole to penetrate a wired capillary tube and connecting a wire between a first conductor and a second conductor, including: positioning the capillary tube on the second conductor and performing ball welding, thereby A step of forming a bump on the second conductor; after moving the capillary upward, the capillary is moved laterally to a position opposite to the first conductor, and then the capillary is lowered to cut the line and cut the line A step of forming an inclined surface on the upper part of the block; a step of performing a bonding to connect one end of the wire to the first conductor; and a second bonding so that the capillary is positioned on the inclined surface of the upper portion of the bump, and then using the capillary The line that will extend from inside the capillary 313975.ptd Page 23 564538 6. Scope of patent application The step of connecting to the inclined surface of the upper part of the bump and cutting the line near the joint. 4. For the wire bonding method of the third item of the patent application, wherein the inclined surface of the upper portion of the bump is formed as a flat surface or a concave surface, and the two joining steps include placing the capillary on the inclined surface of the upper portion of the bump, and then use The bottom of the capillary presses the wire on the inclined surface of the upper part of the bump. 5. For the wire bonding method according to item 3 or 4 of the scope of the patent application, wherein the inclined surface of the upper portion of the bump is an inclined angle formed by a straight line connecting both ends of the inclined surface with respect to the second conductor surface. The first conductor is formed to have an opening angle of 2 ° to 60 °. 6. —A method of forming a bump is to perform a single bonding on the first conductor and a second bonding on the second conductor to connect the wire between the first conductor and the second conductor in advance. A method of forming a bump on the second conductor by ball bonding includes: a step of lowering a capillary tube onto the second conductor, and connecting a ball formed at the front end of the wire to the second conductor to form a bump; and thereafter, forming the bump A step for the capillary to rise vertically; thereafter, a step for laterally moving the capillary in a direction opposite to the direction where the first conductor is located; and thereafter, lowering the capillary to crimp the bottom of the capillary to the bump Step; and thereafter, a step of laterally moving the capillary in the direction of the first conductor, and an inclined surface is provided on an upper portion of the bump. 313975.ptd Page 24 564538 6. Application for patent scope 7. For the method of forming a bump in item 6 of the scope of patent application, wherein the inclined surface on the upper part of the bump is opposite to the straight line connecting the two ends of the inclined surface. The inclination angle formed on the second conductor surface is formed so as to extend to an opening angle of 2 ° to 60 ° of the first conductor. 8. —A method of forming a bump is to perform a single bond on the first conductor and a second bond on the second conductor to connect the wire between the first conductor and the second conductor in advance. A method of forming a bump on the second conductor by ball bonding includes: a step of lowering a capillary tube onto the second conductor, and connecting a ball formed at the front end of the wire to the second conductor to form a bump; and thereafter, forming the bump A step of vertically raising the capillary; a step of laterally moving the capillary toward the position of the first conductor; a step of vertically raising the capillary; and a step of moving the capillary toward the first conductor A step of laterally moving the opposite direction of the position; thereafter, a step of lowering the capillary and crimping the bottom of the capillary to the bump; and thereafter, laterally moving the capillary toward the position of the first conductor In the moving step, an inclined surface is provided on the upper portion of the bump. 9. For the method for forming a bump in item 8 of the scope of patent application, wherein the inclined surface of the upper portion of the bump is an inclination angle formed by a straight line connecting both ends of the inclined surface with respect to the second conductor surface as The first conductor is formed to have an opening angle of 2 ° to 60 °. 313975.ptd Page 25 564538 VI. Patent application scope 1 0 — A kind of bump, which is bonded once on the first conductor and twice on the second conductor to connect the wire to the first conductor Between the second conductor and the second conductor, a bump formed in advance on the second conductor by ball welding is characterized in that it has an upper surface formed as a flat surface or a concave surface. The inclination angle formed by the second conductor surface is formed so as to extend toward the first conductor at an angle of 2 ° to 60 °. Page 26 313975.ptd