JP5510691B2 - Bonding capillary - Google Patents

Description

  An aspect of the present invention relates to a bonding capillary, and more specifically, to a bonding capillary suitable for connection with a hard bonding wire such as copper.

  In wire bonding in which a semiconductor element and a lead frame lead are connected by a fine metal wire, one end of the fine metal wire (bonding wire) is pressure-bonded to the electrode pad using a bonding capillary (first bond), and then the fine metal wire is routed to lead. Crimp to (second bond). When crimping a thin metal wire, reliable crimping is realized by applying ultrasonic waves while pressing the fine metal wire with a bonding capillary.

  In recent years, attempts have been made to use copper, which is lower in cost than gold, as a material for bonding wires. However, in copper wire bonding, since the copper wire is hard, it is difficult to obtain a high bonding strength, and the tip of the bonding capillary is easily worn. For this reason, there exists a problem that the replacement frequency of a bonding capillary becomes high compared with the case where a gold wire is used.

  Patent Document 1 discloses a bonding capillary that has a rounded unevenness on the front end surface of the bonding capillary, thereby reducing the amount of deposits on the front end surface and extending the life. Patent Document 2 discloses a structure in which the particle structure of the material is exposed at a part of the tip of the bonding capillary as a bonding capillary that can extend the life.

  However, in any of the techniques of Patent Documents 1 and 2, there is room for improvement in order to improve the gripping force on the bonding wire and maintain the initial bonding strength for a long period of time. In particular, when a bonding wire that is harder than a gold wire, such as a copper wire, is used, problems such as a decrease in bonding strength and a decrease in life due to wear become significant.

Japanese Utility Model Publication No. 62-190343 Special table 2009-540624

  The present invention has been made on the basis of recognition of such a problem, and an object thereof is to provide a bonding capillary that can maintain a sufficient bonding strength for a long period of time.

1st invention is equipped with the main-body part which has the front end surface to which wire bonding is carried out, The said front end surface has fine uneven | corrugated shape, The sharpness of the front-end | tip of the convex part in the said uneven | corrugated shape is the tip of the recessed part in the said uneven | corrugated shape. rather smaller than pointed, the area of the convex portion when viewed from a direction perpendicular to the front end surface is larger than the area of the recess, the skewness of the tip surface is at -0.3 or less, and said front end surface The average height of the bonding capillary is 0.06 micrometer or more and 0.3 micrometer or less .

According to this bonding capillary, it is possible to maintain the bonding strength over a long period of time even if repeated bonding is performed while securing the initial bonding strength.
According to this bonding capillary, the contact area with the wire is increased and a steep slope is formed toward the recess, so that the grip force between the tip surface and the bonding wire is increased.
According to this bonding capillary, there is little change in shape due to wear during use, and the initial bonding strength can be maintained for a long time even if repeated bonding is performed.

The second invention includes a main body having a tip surface for wire bonding, the tip surface has a fine concavo-convex shape, and the tip of the convex portion in the concavo-convex shape has a concave portion in the concavo-convex shape. tip smaller than pointed, the area of the convex portion when viewed from a direction perpendicular to the front end surface is much larger than the area of the recess, the skewness of the tip surface is at -0.43 or less, and wherein The average height of the front end face is a bonding capillary characterized by being 0.16 micrometers or more and 0.3 micrometers or less .

According to this bonding capillary, it is possible to maintain the bonding strength over a long period of time even if repeated bonding is performed while securing the initial bonding strength.
According to this bonding capillary, the contact area with the wire is increased and a steep slope is formed toward the recess, so that the grip force between the tip surface and the bonding wire is increased.
According to this bonding capillary, there is little change in shape due to wear during use, and the initial bonding strength can be maintained for a long period of time even after repeated bonding.

  According to this bonding capillary, there is little change in shape due to wear during use, and the initial bonding strength can be maintained for a long time even if repeated bonding is performed.

According to a third aspect of the present invention, there is provided the bonding capillary according to the first or second aspect, wherein the maximum peak height of the tip surface is not more than 0.9 times the average height.

  According to this bonding capillary, there is little change in shape due to wear during use, and the initial bonding strength can be maintained for a long time even if repeated bonding is performed.

According to a fourth aspect of the present invention, there is provided the bonding capillary according to any one of the first to third aspects, wherein an average particle diameter of the crystal exposed on the tip surface is 1.2 micrometers or less. is there.

  According to this bonding capillary, if the average particle size of the ceramic crystals is 1.2 micrometers or less, the wear of the tip surface can be reduced.

In addition, according to a fifth invention, in any one of the first to fourth inventions, the main body portion is provided on the distal end surface side and is provided with a hole through which a bonding wire is inserted, and between the hole and the distal end surface. And the concavo-convex shape of the tip surface is at least 20 micrometers in a direction away from the hole along the tip surface from the edge of the chamfered portion of the tip surface. A bonding capillary characterized in that it is determined by a roughness curve measured at least at a length of 100 micrometers in the surface region.

  According to this bonding capillary, for any one of the first to fifth inventions, sufficient bonding is possible as long as it is an uneven shape obtained by a roughness curve measured at least 100 micrometers in length in the surface region. The strength can be maintained for a long time.

  According to the aspect of the present invention, a bonding capillary that can maintain a sufficient bonding strength for a long period of time is provided.

FIG. 1 is a schematic view illustrating a bonding capillary according to this embodiment. FIG. 2 is a schematic enlarged view illustrating the tip shape of the bonding capillary according to this embodiment. FIG. 3 is a schematic enlarged view illustrating the distal end face of the bonding capillary according to this embodiment. FIG. 4 is a schematic cross-sectional view illustrating the state of wire bonding. FIGS. 5A and 5B are diagrams illustrating the uneven shape of the distal end surface in the present embodiment. 6A and 6B are diagrams illustrating the uneven shape of the tip surface in the reference example (No. 1). FIGS. 7A and 7B are diagrams illustrating the uneven shape of the tip surface in the reference example (No. 2). FIG. 8 is a diagram illustrating the evaluation results of Examples and Comparative Examples. FIG. 9 is a schematic perspective view illustrating a measurement region. FIG. 10 is a diagram illustrating the determination result of the bonding strength. FIGS. 11A and 11B are diagrams illustrating changes in Cpk depending on the number of bondings. 12A and 12B are views illustrating a part of the manufacturing method of the bonding capillary. FIG. 13 is a diagram illustrating a method for measuring the average particle size of ceramic crystals. FIG. 14 is a diagram illustrating the relationship between the average particle diameter of ceramic crystals and the lifetime.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

(Embodiment)
FIG. 1 is a schematic view illustrating a bonding capillary according to this embodiment.
FIG. 2 is a schematic enlarged view illustrating the tip shape of the bonding capillary according to this embodiment.
FIG. 3 is a schematic enlarged view illustrating the distal end face of the bonding capillary according to this embodiment.
FIG. 1 shows the entire bonding capillary 110. FIG. 2 shows an enlarged view of part A shown in FIG. FIG. 3 shows a perspective view of the front end surface as viewed obliquely from below.

  As shown in FIG. 1, the bonding capillary 110 has a main body 10 having a distal end surface 50. The main body 10 has a cylindrical portion 11 having a diameter for mechanically fixing to the bonding apparatus, a conical portion 12 provided on the distal end side of the cylindrical portion 11, and a position aimed at avoiding the adjacent wired fine metal wires And a bottleneck portion 13 for performing bonding. The front end surface 50 is an end surface on the front end side of the bottle neck portion 13.

  Inside the bonding capillary 110, a hole for inserting a fine metal wire (bonding wire) is provided so as to penetrate in the axial direction. The cylindrical portion 11 has a diameter that can be mechanically fixed to the bonding apparatus. The diameter of the cone portion 12 becomes smaller toward the tip side. The conical part 12 has, for example, a truncated cone shape, and the diameter on the cylindrical part 11 side is substantially equal to the diameter of the cylindrical part 11.

  As shown in FIG. 2, the bottle neck portion 13 is provided on the bonding side of the conical portion 12. The bottleneck portion 13 has a diameter such that wire bonding can be performed at a predetermined bonding position while avoiding adjacent fine metal wires that are already wired. For example, the diameter of the bottleneck portion 13 gradually decreases from the root side (cone portion 12 side) toward the distal end surface 50 side. In particular, the diameter on the root side becomes smaller in a curve.

  By narrowing the outer diameter of the bottleneck portion 13, it is possible to cope with high-density wire bonding in which the pitch of bond positions (bonding positions) is as small as 50 micrometers (μm) or less, for example. That is, if the diameter of the bottleneck part 13 is reduced, even if the interval between the joining positions is narrow (when high-density wire bonding is performed), the adjacent metal thin wire already wired and the bottleneck part 13 Can prevent interference.

  As shown in FIG. 3, a hole 11 h through which a bonding wire is inserted is provided on the distal end face 50 side of the bonding capillary 110. A chamfered portion 13c (chamfer portion) is provided between the hole 11h and the tip surface 50. The chamfered portion 13c has a surface provided, for example, in a curved shape from the edge of the hole 11h to the tip surface 50.

FIG. 4 is a schematic cross-sectional view illustrating the state of wire bonding.
FIG. 4 shows the state of the second bonding.
A bonding wire (hereinafter referred to as a wire) BW inserted through the hole 11h of the bonding capillary 110 is first bonded. Thereafter, the bonding capillary 110 is drawn around the lead 200 in a predetermined track to form a loop in the wire BW.

  When the bonding capillary 110 is pressed onto the lead 200, the wire BW is sandwiched between the tip surface 50 and the lead 200. Since the distal end surface 50 is inclined toward the chamfered portion 13 c, the distance between the distal end surface 50 and the lead 200 becomes narrower from the outer side to the inner side of the distal end surface 50. Therefore, the thickness of the wire BW sandwiched between the distal end surface and the lead 200 becomes thinner from the outer side to the inner side of the distal end surface 50. The wire BW is divided at the edge position of the chamfered portion 13c.

  For example, an ultrasonic wave is applied to the bonding capillary 110 in a state where the wire BW is sandwiched between the tip surface 50 and the lead 200. Thereby, the wire BW is crimped to the lead 200. After crimping the wire BW, the bonding capillary 110 is raised. Thereby, the wire BW is connected between the electrode pad and the lead 200.

  In such wire bonding, since the bonding capillary 110 applies ultrasonic waves in a state where a pressing force is applied to the wire BW, the grip force between the distal end surface 50 and the wire BW becomes important. When the grip force is weak, ultrasonic vibration is not efficiently applied between the wire BW and the lead 200, and the bonding force between the wire BW and the lead 200 tends to be weak.

  On the other hand, if the pressing force and the ultrasonic amplitude are increased to secure the bonding force, the tip surface 50 is easily worn. When the distal end surface 50 is worn and a desired grip force cannot be obtained, the bonding capillary 110 needs to be replaced. When the replacement frequency of the bonding capillary 110 is high, the bonding apparatus must be frequently stopped, which affects the manufacturing time.

  As shown in FIG. 3, the tip surface 50 of the bonding capillary 110 according to the present embodiment has a fine uneven shape. The sharpness of the tip of the convex portion in the concave and convex shape is smaller than the sharpness of the tip of the concave portion in the concave and convex shape. Thereby, in the bonding capillary 110, a desired grip force is maintained for a long time.

Here, the concave-convex shape of the tip surface will be described.
FIGS. 5A and 5B are diagrams illustrating the uneven shape of the distal end surface in the present embodiment.
6A and 6B are diagrams illustrating the uneven shape of the tip surface in the reference example (No. 1).
FIGS. 7A and 7B are diagrams illustrating the uneven shape of the tip surface in the reference example (No. 2).
5-7, (a) represents the measurement value of the uneven | corrugated shape by the three-dimensional scanning electron microscope of a front end surface, (b) represents the image figure of a roughness curve.

The concavo-convex shape of the front end surface is expressed by, for example, an average height Rc and a skewness (distortion degree) Rsk.
The average height Rc and the skewness Rsk are calculated based on JIS B 0601-2001.
In this embodiment, the roughness curve of the tip surface was measured under the following conditions.
Measuring instrument: Laser microscope (Olympus, OLS4000)
Measurement magnification: 50 times Cut-off (phase compensation type high-pass filter) λc: 25 μm

  From the roughness curve measured under the above conditions, the average height Rc is obtained by the following equation (1), and the skewness Rsk is obtained by the following equation (2).

In Equation (1), m is the number of contour curve elements, and Zti is the average height of the contour curve elements.
In the equation (2), Zq is a root mean square height, and Zn is a height value in the roughness curve.

  The average height Rc of the tip surface 50 in this embodiment shown in FIGS. 5A and 5B is 60 nanometers (nm) or more, and the skewness Rsk is about −1.2 or more, −0.3. It is as follows.

  In the reference example (part 1) shown in FIGS. 6A and 6B, the average height Rc of the tip surface 51 is 10 nm to 15 nm, and the skewness Rsk is 0.3 to −0.5.

  In the reference example (part 2) shown in FIGS. 7A and 7B, the average height Rc of the tip surface 52 is 150 nm to 280 nm, and the skewness Rsk is 0.2 to −0.25.

  Thus, the skewness Rsk of the front end face 50 in this embodiment is −0.3 or less. Further, the skewness Rsk can be set to −1.2 or more. The skewness Rsk represents the symmetry between the concavo-convex peaks (convex) and valleys (concave). If the uneven shape is a sine distribution, the skewness Rsk is zero. The skewness Rsk is negative when the area of the peak (convex) is larger than the area of the valley (concave) when viewed in the direction perpendicular to the tip surface 50 (the convexity is smaller than the concaveness). Represents.

  In the bonding capillary 110 of this embodiment having the tip surface 50, both the initial bonding strength and the life are good. On the other hand, in the bonding capillary having the tip surface 51 in the reference example (part 1), the initial bonding strength is insufficient. In the bonding capillary having the tip surface 52 in the reference example (part 2), the initial bonding strength is good, but the life is short.

  The sharpness of the tip of the convex portion in the concavo-convex shape of the tip surface 50 is smaller than the sharpness of the tip of the concave portion in the concavo-convex shape. Will be able to maintain.

  Further, since the skewness Rsk of the tip surface 50 is negative and the area of the peak (convex) is larger than the area of the valley (concave), the contact area between the tip surface 50 and the wire BW is increased and it is directed to the concave portion. Therefore, the grip force between the tip surface 50 and the wire BW increases.

  That is, in the bonding capillary 110 having the tip surface 50, it is possible to realize a long-life product having excellent wear resistance while sufficiently securing the initial bonding strength. In the bonding capillary 110 of the present embodiment, sufficient bonding strength can be obtained even when performing bonding bonding using a hard wire BW such as copper. In addition, since the tip face 50 is excellent in wear resistance, the initial bonding strength is maintained for a long time even if the bonding with a hard wire BW such as copper is repeated.

(Example)
Next, examples of the bonding capillary 110 according to the present embodiment will be described.
FIG. 8 is a diagram illustrating the evaluation results of Examples and Comparative Examples.
FIG. 9 is a schematic perspective view illustrating a measurement region.
In FIG. 8, the average height Rc, skewness Rsk, and maximum peak height Rp at the tip surfaces of Examples 1 to 6 and Comparative Examples 1 to 8 are shown.

  The average height Rc, skewness Rsk, and maximum peak height Rp in each example are values measured in the surface region 50r shown in FIG. That is, as illustrated in FIG. 9, the surface region 50 r is a region having a length L <b> 1 in the direction away from the hole 11 h along the tip surface 50 from the edge of the chamfered portion 13 c in the tip surface 50. The length L1 is at least 200 μm. The measurement length L2 is about 100 μm within the range of the surface region 50r. In the present embodiment, the line roughness at a measurement length L2 of 100 μm is measured at three locations in the surface region 50r, and the average is obtained.

  The bond strength Cpk shown in FIG. 8 is a process capability index. In each example shown in FIG. 8, when the average of the bonding strength of the wire BW is Ave and the lower limit standard of the bonding strength is 3 gram weight (gf), the calculation is performed by Cpk = (Ave−3gf) / 3σ. The bonding strength is a strength in a pull test in the second bond. The number of samples is 30. In general, the joint strength Cpk in wire bonding is required to be 1.67 or more.

  As shown in FIG. 8, in Examples 1 to 6 and Comparative Examples 1 to 8, combinations of the average height Rc, the skewness Rsk, and the maximum peak height Rp are different. Among these, in Examples 1-6 and Comparative Examples 4-8, Cpk of joining strength becomes 1.67 or more.

FIG. 10 is a diagram illustrating the determination result of the bonding strength.
In FIG. 10, the results of the joint strength determination are shown for Examples 1 to 6 and Comparative Examples 4 to 6 in which the joint strength Cpk is 1.67 or more in the example shown in FIG.

  The determination of the bonding strength is performed based on whether or not Cpk is less than 1.67 for the initial Cpk and the Cpk after the number of wire bondings of 500,000 and 1 million. In the bonding strength determination of FIG. 10, “OK” is indicated when each Cpk is 1.67 or more, and “NG” is indicated when it is less than 1.67.

  As shown in FIG. 10, in Examples 1 to 6 and Comparative Examples 4 to 6, all the initial bonding strength determinations are “OK”. After 500,000 times of wire bonding, Examples 1 to 6 are “OK”, but Comparative Examples 4 to 6 are all “NG”. After 1 million times of wire bonding, Examples 1 to 3, 5 and 6 are “OK”, and Example 4 and Comparative Examples 4 to 6 are “NG”. After 1.5 million wire bondings, Examples 5 and 6 are “OK”, and Examples 1 to 4 and Comparative Examples 4 to 6 are “NG”.

FIGS. 11A and 11B are diagrams illustrating changes in Cpk depending on the number of bondings.
11A shows changes in Cpk of Example 2 shown in FIGS. 8 and 10, and FIG. 11B shows changes in Cpk of Comparative Example 6 shown in FIGS. Has been.

  As shown in FIG. 11A, with respect to the bonding capillary having the tip surface of Example 2, the initial bonding strength is maintained even after exceeding 1 million times from the initial bonding, and the Cpk of 1.67 or more is maintained. Persists.

  On the other hand, as shown in FIG. 11B, for the bonding capillary having the tip surface of Comparative Example 6, the Cpk at the initial stage of bonding is 1.67 or more, but the Cpk from around 300,000 times. A marked decrease is observed, falling below 1.67.

  From the above results, it is preferable that the skewness Rsk of the tip surface 50 is about −1.2 or more and −0.3 or less, and the average height Rc of the tip surface 50 is 0.06 μm or more and 0.3 μm or less. . If the average height Rc is 0.06 μm or more, the grip force is small, and in particular, when a copper wire BW is used, sufficient bonding strength cannot be obtained. On the other hand, when the average height Rc exceeds 0.3 μm, it becomes difficult to form unevenness of −0.3 or less as the skewness Rsk. More preferably, the skewness Rsk of the tip surface 50 is about −1.2 or more and −0.43 or less, and the average height Rc of the tip surface 50 is 0.16 μm or more and 0.3 μm or less. As a result, the initial bonding strength can be maintained even after 1,500,000 times from the initial bonding.

  Further, the maximum peak height Rp of the tip surface 50 is preferably 0.9 times or less (Rp / Rc ≦ 0.9) of the average height Rc. Rp / Rc can be 0.5 times or more. When Rp / Rc exceeds 0.9, it becomes difficult to maintain the initial bonding strength for a long period of time. On the other hand, when Rp / Rc is 0.9 or less, the shape change due to wear during use is small, and the initial bonding strength is maintained for a long time.

(Production method)
Next, a method for manufacturing the bonding capillary 110 according to this embodiment will be described.
12A and 12B are views illustrating a part of the manufacturing method of the bonding capillary.
FIGS. 12A and 12B show a procedure for forming the concavo-convex shape of the tip surface 50 in the method for manufacturing the bonding capillary 110.

  The material of the bonding capillary 110 according to the present embodiment includes, for example, aluminum (Al) and zirconia (Zr). As shown in FIG. 12A, the bonding capillary 110 is dotted with Zr having a small particle diameter in Al having a large particle diameter. When the tip surface 50 is polished, the tip surface 50 is in a state where the Zr crystal is exposed on the surface of the Al base material.

In this state, the tip surface 50 is sandblasted. An example of sandblasting conditions is abrasive grain type, spraying pressure, spraying time. By optimizing the sandblasting conditions, Zr crystals softer than Al fall off from the surface of the Al base material. Thereby, as shown in FIG. 12B, a recess is formed in a part of the flat surface of the tip surface 50. At this time, since the ratio of Zr to the Al base material is small, the area of the recess formed by dropping the crystal of Zr does not become larger than the area of the protrusion (flat surface).
In addition, said manufacturing method is an example and can manufacture also by methods other than sandblasting.

(Crystal particle size)
Next, the crystal particle diameter of the bonding capillary will be described.
In the bonding capillary 110 according to the present embodiment, the average particle diameter of the ceramic crystals exposed on the tip surface 50 is 1.2 μm or less. The average particle size of the ceramic crystals can be 0.3 μm or more. When the average particle diameter of the ceramic crystals is 1.2 μm or less, the wear of the tip face 50 is reduced and the life of the bonding capillary 110 is extended.

FIG. 13 is a diagram illustrating a method for measuring the average particle size of ceramic crystals.
FIG. 13 shows an SEM (Scanning Electron Microscope) image in a state in which the surface of the ceramic sample is polished and then subjected to thermal etching to clarify the boundary between particles.

  First, an arbitrary part of the sample is observed with a SEM at a magnification of about 10,000 to 30,000 times to obtain an SEM image. And based on the acquired SEM image, an average particle diameter is calculated by the planimetric method, for example.

The average particle size is calculated by the following procedure.
First, a known circle CIR having an area A (μm ² ) is drawn on the acquired SEM image. Next, the number nc of particles contained inside the circle CIR and the number ni of particles on the circle CIR (on the circumference) are counted. And using this nc and ni, an average particle diameter is calculated by the following formula | equation.
N = (nc + (1/2) ni) / (A / magnification ² )
Average particle diameter (μm) = 2 / (π · N) ^1/2

FIG. 14 is a diagram illustrating the relationship between the average particle diameter of ceramic crystals and the lifetime.
FIG. 14 shows the result of determining the lifetime of the bonding capillary according to the number of bondings for several types of average particle diameters. The number of times of bonding is 500,000 times and 1 million times. The determination of the lifetime indicates “OK” if Cpk is 1.67 or more, and “NG” if it is less than 1.67.

  From the results shown in FIG. 14, in order to maintain Cpk of 1.67 or more even after the number of bondings of 500,000, the average particle diameter of ceramic crystals is preferably about 0.3 μm or more and 1.2 μm or less. Further, a more preferable average particle diameter is about 0.3 μm or more and 0.7 μm or less. When the average particle diameter is 0.7 μm or less, Cpk of 1.67 or more is maintained even after 1 million bondings.

  If the bonding capillary 110 is made of a ceramic having a crystal having such an average particle diameter, wear of the tip face 50 is reduced. Thereby, the lifetime of the bonding capillary 110 is lengthened, and the replacement frequency is reduced.

  As described above, according to the present embodiment, in wire bonding, sufficient bonding strength between the wire BW and the lead 200 can be obtained, and the initial bonding strength can be maintained for a long time even when bonding is repeated. Will be able to.

  The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions. As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention. For example, the shape, size, material, and the like of the bonding capillary 110 are not limited to those illustrated, and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Main-body part, 11 ... Cylindrical part, 11h ... Hole, 12 ... Conical part, 13 ... Bottle neck part, 13c ... Chamfering part, 50 ... Tip surface, 50r ... Surface area, 110 ... Bonding capillary, 200 ... Lead, BW ... wire, CIR ... yen

Claims (5)

A main body having a tip surface for wire bonding is provided,
The tip surface has a fine uneven shape,
The sharpness of the tip of the convex portion of the concavo-convex shape, rather smaller than pointed tip of the concave portion in the uneven shape,
The area of the convex part when viewed from the direction perpendicular to the tip surface is larger than the area of the concave part,
A bonding capillary characterized in that a skewness of the tip surface is −0.3 or less, and an average height of the tip surface is 0.06 μm or more and 0.3 μm or less . A main body having a tip surface for wire bonding is provided,
The tip surface has a fine uneven shape,
The sharpness of the tip of the convex portion in the concave and convex shape is smaller than the sharpness of the tip of the concave portion in the concave and convex shape,
Area of the convex portion when viewed from a direction perpendicular to the front end surface is much larger than the area of the recess,
The skewness of the distal end surface is at -0.43 or less, and Bonn loading capillary, wherein the average height of the tip face is not more than 0.16 micrometers or 0.3 micrometers. Bonding capillary according to claim 1 or 2, wherein the maximum peak height of the tip face is not more than 0.9 times the average height. The bonding capillary according to any one of claims 1 to 3 , wherein an average particle diameter of the crystal exposed on the tip surface is 1.2 micrometers or less. The main body has a hole provided on the tip surface side and through which a bonding wire is inserted, and a chamfered portion provided between the hole and the tip surface,
The concavo-convex shape of the tip surface has a length of at least 100 micrometers in a surface region of at least 20 micrometers in the direction away from the hole along the tip surface from the edge of the chamfered portion of the tip surface. The bonding capillary according to any one of claims 1 to 4 , wherein the bonding capillary is obtained from a measured roughness curve.